Keywords: Gene editing
Emerging trends in genome editing of wild animals
35453Blix, T., Myhr, A.I., Transgenic Research, 35. 2026-02-06 09:37:20.
Globally, nearly one million species are currently threatened with extinction, highlighting the need for more efficient solutions to biological conservation. Genome editing, which allows for faster and more precise changes in genomes, is a promising technique for boosting populations through facilitated adaptation, management of invasive or pathogenic populations, and potentially even facilitating the revival of extinct species. These approaches belong to a new field of research termed conservation biotechnology, which places a great responsibility on researchers and decision makers to ensure sustainability. In this paper, we have mapped the emerging trends in genome editing of wild animals. Current projects primarily focus on population control and de-extinction, with fewer initiatives aimed at preserving threatened species. We then explore four critical dimensions of conservation biotechnology: the technology itself, new perspectives on conservation practices, research organization, and governance and policy. Despite its potential, key questions remain—particularly whether genome editing can increase genetic diversity without causing unintended non-target impacts. Genome editing also provokes new perspectives on conservation practices where ecosystem-wide impact assessment, case-by-case evaluations, and post-release monitoring needs to be prioritized. Furthermore, conservation biotechnology is heavily funded through private funding showing varying stakeholder interest, which can lead to untraditional and less transparent research processes. Stakeholders, including local and indigenous people, are only to a certain degree involved, which may weaken inclusion of local knowledge and monitoring efforts. Finally, concerning governance and policy, there is an urgent need to develop more adequate regulation of conservation biotechnology, as environmental release of genome-edited animals challenges definitions and guidelines in current nature protection laws and GMO regulations. Based on our analysis, we outline key points for further investigation toward a more sustainable approach to conservation biotechnology.
Precision pest management: Genome editing tools, specifically CRISPR/Cas9 and future prospects
35424Ankush Saini, Neha Sharma, Nidhi Sharma, et al., Pesticide Biochemistry and Physiology, 218. 2026-02-03 15:42:17.
The growing resistance to synthetic insecticides and Bt toxins, alongside persistent crop losses despite heavy pesticide application, highlights the urgent need for safer, sustainable and efficient pest management strategies. This review presents genome editing as a precise and versatile approach to reduce pest impact by altering fertility, feeding patterns or vulnerability, while protecting beneficial organisms. Among the genome editing tools, CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9) is one of the most promising genome editing techniques in insects. It facilitates targeted functional studies, integration with RNAi and dual-expression systems and gene drive applications. Deployment is envisioned in two phases, initial laboratory modification followed by regulated field release, with a strong emphasis on biosafety through terminator genes, marked individuals for gene flow monitoring, optimized dosages, stringent screening and long-term ecological surveillance, along with transparency and adherence to international safety protocols. Significant challenges encompass delivery efficiency, identification of edits, off-target mutations, dose-related efficacy and sterility, unstable transmission and resistance development. Innovations such as base and prime editing minimize unintended mutations by circumventing double-stranded breaks (DSBs), while paratransgenic strategies targeting gut symbionts offer supplementary avenues; plant-mediated insect gene editing emerges as a promising frontier. Overall, carefully regulated trials aligned with policy frameworks and stakeholder involvement are vital to assess effectiveness in natural environments and achieve targeted, dependable and ecologically responsible pest control.
Three Stunning Ways Biologists Aim to Edit Animal and Plant Genes to Fight Diseases and Extinction
35386Sandy Ong, Smithsonian Magazine, 2026-01-21 16:42:41.
In the summer of 1904, Herman Merkel, chief forester at the Bronx Zoo, in New York City, was making his usual rounds across the property when he noticed something strange growing on American chestnut trees: misshapen constellations of swollen, orange-brown cankers. Unbeknownst to Merkel, his observations were the first signs of what would later be referred to as “the greatest ecological disaster in North America since the Ice Age.” Further investigation revealed that the culprit was a fungus called Cryphonectria parasitica, or chestnut blight, which slips its spores through cracks in the bark and fatally severs a tree’s water and nutrient supply. The pathogen was a stowaway that had arrived on imported Japanese chestnut trees, which are resistant—but on American soil, it proved to be a swift and merciless killer. Barely a year later, the blight had claimed nearly all the zoo’s chestnuts—as well as those in the surrounding Bronx parks. By the 1950s, it had wiped out 99 percent of the species’ population across the Eastern United States, where more than four billion of the towering trees had once so blanketed the landscape that a squirrel was said to be able to travel from Maine to Georgia on chestnut branches alone. Since then, scientists have tried, with little success, to bring the trees back from the brink. Today, American chestnuts are considered functionally extinct. Full-sized trees are hard to come by; mainly roots and shoots remain. Scientists have bred hybrid American-Chinese chestnut trees, but planting fully native species is important for ecological restoration goals, says Andrew Newhouse, director of the American Chestnut Research and Restoration Project at the State University of New York (SUNY). Thanks to an emerging field, the iconic trees—and other imperiled species—could one day be restored. The discipline, called synthetic biology, relies on editing organisms’ DNA to introduce new genes or modify existing ones, essentially reprogramming life to fight disease, clean up the environment, increase food production and more. For chestnut trees, making changes to their genome could boost their resistance to the blight.
Microhomology-mediated end joining is the predominant form of DNA repair in the mosquito Aedes aegypti with implications for gene editing, gene drive, and transgene removal
35375Joseph S Romanowski, Kevin M Myles, Zach N Adelman, Nucleic Acids Research, 54. 2026-01-20 16:30:25.
Programmable site-specific nucleases have revolutionized the field of genetics, and in the field of mosquito vector control, gene editing by these tools has inspired a new wave of population control approaches that aim to prevent disease transmission. Little is known of how DNA repair is prioritized in mosquitoes, which diverged from the nearest model system (Drosophila) by >200 million years, despite site-specific gene editing now being commonplace. Here, we report a scalable, high-throughput platform for studying DNA double-stranded DNA break (DSB) repair in mosquitoes by delivering CRISPR/Cas9, I-SceI, or other nucleases to Aedes aegypti embryos, capable of measuring single-strand annealing (SSA), non-homologous end joining, and microhomology-mediated end-joining (MMEJ) repair outcomes. We find CRISPR/Cas9 can induce deletions of up to 8.6 kb through SSA repair and is tolerant of resection distances of 3.5 kb. Indel events were insensitive to lig4 knockouts, and across 20 synthetic guide RNAs (sgRNAs) representing 5 locations in 2 transgenic strains were almost exclusively attributed to MMEJ repair, establishing MMEJ as the dominant form of repair in A. aegypti at CRISPR/Cas9 DSBs. This information is critical to our understanding of how DNA repair shapes processes required for genetic control strategies involving gene drive action/resistance as well as transgene stability.
Researchers Use Gene Editing to Separate Male and Female Mosquitoes
35367ISAAA Inc., 2026-01-14 11:04:44.
Researchers from the Hebrew University of Jerusalem have developed a new genetic method to separate male and female mosquitoes, which is highly beneficial for large-scale mosquito control programs. Led by Doron Zaada and Prof. Philippos Papathanos, the study aims to improve existing separation strategies that are labor-intensive, difficult to scale, and rely on releasing only male mosquitoes. The study focused on the Asian Tiger mosquito (Aedes albopictus), a major carrier of diseases such as dengue, chikungunya, and Zika. Using CRISPR, the researchers developed a genetically engineered “Genetic Sexing Strain” by disrupting the mosquito's yellow pigmentation gene, then restored dark pigmentation only in males by linking the gene to nix, a “master switch” that converts females into fertile males. This resulted in a stable strain in which males are dark-colored, and females are yellow. The study also found that the yellow females lay eggs that cannot survive dry conditions, unlike wild mosquito eggs that can survive for months. The genetically converted males were shown to behave and reproduce like natural males, indicating their effectiveness for vector control programs. The researchers said that the next step is to improve the female mosquitoes' ability to survive high temperatures or specific additives used in mosquito mass-rearing biofactories.
Researchers develop temperature-controlled gene-editing method to potentially improve efforts to control disease-carrying insects
35356Caliann Ferguson, UT Health Houston School of Public Health, 2026-01-06 09:54:29.
New research presents promising results from an innovative technique that utilizes temperature control to genetically engineer sterile populations of insects, such as mosquitoes responsible for diseases like malaria, dengue, and other vector-borne illnesses. Led by researchers at UTHealth Houston School of Public Health, the Nature Communications publication leverages historical and traditional sterilization insect techniques (SIT) and applies an innovative method that can be scaled for larger population protection. Used for decades, traditional SITs include releasing large numbers of sterile males into mosquito populations so that when they mate with wild females, no viable offspring are produced. CRISPR/Cas9-based methods have proven challenging as they require breeding two separate lines of engineered insects and carefully sorting those insects to produce and release only sterile males. Led by principal investigator Victor Lopez Del Amo, PhD, assistant professor of epidemiology, and Christina Nguyen, a research technician, who carried out most of the experiments, this promising method aims to simplify the traditional SIT by harnessing a gene-editing tool called CRISPR-Cas12a that can generate male sterility and female lethality in a temperature-controlled manner. Cas12a can be engineered to be inactive at lower temperatures and active at higher temperatures. This property enabled the team to develop a single genetically modified insect strain that possesses the genetic composition necessary to disrupt key fertility and reproductive genes.
New Gene Drive Stops the Spread of Malaria—Without Killing Any Mosquitoes
35343Shelly Fan, SingularityHub, 2025-12-18 11:51:00.
Mosquitoes are an uncomfortable, itchy nuisance. But for people in sub-Saharan Africa, a bite could mean death. The pests are living incubators for the parasite that causes malaria. Roughly 600,000 people are killed by the disease each year, with most being children under five years of age. Insecticides, malaria drugs, and mosquito nets saved a million lives globally in 2024 alone. But their efficacy is waning. Mosquitoes and the malaria parasite are becoming resistant to chemical inhibitors. And consistent, perfect use of physical barriers is hard to manage for years on end, especially for children. Realizing this, scientists have turned to a drastic solution: Gene drives, a technology that skews the rules of inheritance. Rather than nature’s fifty-fifty chance of an offspring inheriting a gene from either parent, gene drives raise the possibility of a gene’s inheritance to over 90 percent—if not higher. The tweak allows a gene to rapidly spread across entire populations. In lab tests encoding gene drives that reduce female mosquito fertility, mosquito populations have collapsed. Other experimental gene drives encoding genes that block parasite reproduction have suggested they could replace a natural population with one unable to carry malaria in just a few generations.
Should we edit nature?
35176David Farrier, Aeon, 2025-09-26 14:10:35.
At the end of August 1939, the German archaeologist Otto Völzing discovered around 200 fragments of carved mammoth ivory at the back of a cave in southern Germany. With war just a week away, Völzing’s find was hurriedly collected in a box, where it lay unnoticed in a museum archive for decades. It wasn’t until the 1960s, when the shards were inventoried, that something astonishing emerged out of the heap of broken pieces. They formed an incomplete figurine, with a chimeric mix of features: the body of person, and the head and forearms of a cave lion. Subsequent excavations in the 1970s found further pieces of what has come to be called the Lion-Man of Hohlenstein-Stadel. Carved from a mammoth tusk around 40,000 years ago, it is one of the earliest examples of the human capacity to imagine forms that don’t exist in nature. Every age of human history since the Lion-Man has tried to think beyond nature. In Hesiod’s Theogony, composed around 700 BCE, the chimera was a compound being with the head of a lion, the body of a dragon, and a snake’s-head tail (and an extra goat’s head protruding from its back for good measure). In W B Yeats’s poem ‘The Second Coming’ (1920), a similar ‘rough beast’ is a harbinger of ruin. In our own time, the chimeras are something different. Living things in every part of the biosphere have been forced by climate change, pollution and the spread of non-native species to adapt their bodies and behaviours to a human planet. They may not have visibly merged forms like the Lion-Man, but they do bear the impression of another species: us.
Sequence and expression analysis of potential spermatogenesis-specific gene cognates in the Caribbean fruit fly, Anastrepha suspensa
35118Alfred M. Handler, Richard B. Furlong, Chao Chen, Daniel A. Hahn, Insect Science, 2025-09-08 08:26:08.
The sterile insect technique (SIT) is a highly effective biologically-based method for the suppression of many insect pest populations. SIT efficacy could be improved by methods of male sterilization that avoid the use of irradiation that can result in diminished fitness and mating competitiveness. Alternative sterilization methods include conditional disruption of genes for male fertility, or using their sperm-specific promoters to drive the expression of genes for lethal effectors. Testing has begun for the testis-specific β2-tubulin gene, though additional male fertility genes are required for redundancy or replacement, and for species where the β2-tubulin isoform does not exist or is not testis-specific. Here we had the goal of identifying and characterizing the sequence and transcriptional expression of two genes in the caribfly, Anastrepha suspensa, that are cognates of D. melanogaster spermatocyte-specific male fertility genes. In Drosophila, wampa encodes a coiled-coil dynein subunit required for axonemal assembly essential to microtubule-based sperm motility, while Prosα6T is a proteasome subunit gene required for spermatid individualization and nuclear maturation. In A. suspensa a cognate to wampa exhibited testis-specific transcript expression, which was minimal in both male and female body tissue. A Prosα6T cognate was not apparent in A. suspensa, but its constitutive isoform, Prosα6, expresses in male testes, but also in male and female body tissue. Thus, for A. suspensa, wampa remains a strong candidate gene for male sterility strategies for SIT including a direct target for gene-editing knockout and use of its promoter for testis-specific toxicity or cell death in conditional expression systems.
CRISPR Mosquitoes That Can’t Bite
35031Science Techniz, 2025-08-09 19:49:44.
Scientists have used CRISPR gene editing to alter female mosquitoes so that their proboscis — the needle-like mouthpart used to pierce skin — develops like a male’s. The consequence is simple and profound: modified females can no longer pierce skin and therefore cannot take a blood meal or transmit human diseases like malaria and dengue. Researchers identified a gene involved in the developmental pathway that produces the female proboscis morphology. Using CRISPR-based edits, they altered that gene’s function so that genetically female mosquitoes develop a male-like mouthpart. Because males naturally do not bite (they feed on nectar), the modification removes the biting behavior without fundamentally disrupting other survival traits in lab tests. It’s important to stress that this is a high-level description intended to explain the concept, not a protocol or “how-to.” The work is complex, tightly regulated, and performed under strict laboratory and ethical oversight.
Genome Editing in Insect Pest Control: Importance, Strategies, and Future Implications
35011Ipsita Samal, Tanmaya Kumar Bhoi, Deepak Kumar Mahanta, Ansh Raj, J. Komal, Alagesan Keerthana, Vinod Kumar Dubey, Genome Editing for Pest Management, 2025-08-06 11:45:12.
Genome editing is a cutting-edge tool in biotechnology which brought about substantial changes in a variety of areas, including agriculture and pest control. As properly managing insect pests is critical for protecting food supplies and ensuring produce security, insect species frequently cause severe problems by destroying crop production, resulting in significant financial losses, food scarcity, and insufficiency. Innovative breakthroughs in pest management technology have lately resulted in the replacement of traditional chemical pesticide applications with environmentally safe and non-polluting interventions. Genome editing has the potential to transform pest control by providing precise and targeted therapies for insect pests that can be managed permanently. Researchers have discovered that genome editing methods have created new possibilities for improving food safety, agricultural productivity, and sustainable agriculture affected by pests. Scientists may now offset insect-related shortcomings with creative ways and strategies that ensure environmentally friendly and sustainable farming practices and environmental preservation, thanks to the application of genome editing tools. This chapter focuses on the use of these state-of-the-art technologies in genome editing tools such as ZFN, TALEN, and CRISPR/Cas9 enables us to assess the viability of insect control strategies, that provide significant promise for next-generation approaches to several major pest management problems and allow the insertion of precisely tailored modifications into the genetic composition of pests. To fully utilize the technology and specifically its implications for more efficient management of insect pests, study, analysis, and collaboration across many sectors are essential, which has been centralized in the current chapter.
Can the world survive without mosquitoes and should we even try to find out?
34934Sowjanya Pedada, LA Post, 2025-06-17 15:08:22.
Scientists have developed gene editing technology that could wipe out malaria-carrying mosquitoes within subsequent generations, offering hope against diseases like Malaria, which kills nearly 600,000 people each year. But as field trials approach, bioethicists warn that deliberately driving a species to extinction raises profound questions about our right to reshape nature. Communities in hard-hit regions now face a difficult tradeoff: accept ecological risks or continue losing lives to preventable mosquito-borne diseases. Mosquito-borne diseases extend far beyond Malaria. Dengue infects up to 3.9 billion people annually across 132 countries, causing approximately 40,000 deaths each year. Zika, documented in 89 countries, can cause severe congenital disabilities like microcephaly. The CDC calls mosquitoes the “world’s deadliest animal,” responsible for over 700,000 deaths each year. In sub-Saharan Africa, scientists at Target Malaria have developed genetic modifications that render female mosquito offspring infertile, causing populations to collapse within a few generations in lab tests. “There are so many lives at stake,” said Alekos Simoni, a molecular biologist with the group. Their method uses male mosquitoes to spread ovary-disrupting genes throughout wild populations. Gene-driven mosquito extinction has ignited ethical debate. A recent study published in Science concluded that deliberately wiping out a species may be justifiable, but only under rare, extreme conditions. “These cases highlight the tension between the intrinsic value of a species and the benefits of eradicating a harmful pest,” said Clare Palmer, a bioethicist at Texas A&M. Environmental experts warn of ecological risks, but scientists stress that only a few mosquito species, mainly malaria-spreading Anopheles, would be targeted. “Extinction is not a likely outcome, nor even a desirable one,” said Tony Nolan of the Liverpool School of Tropical Medicine. “It’s not necessary to make the mosquito extinct to eliminate malaria.”
Efficient CRISPR-Cas9-mediated genome editing of the cane toad (Rhinella marina)
34887Michael Clark, Alexander T. Funk, Alex Paporakis, et al., bioRxiv, 2025-06-02 19:02:13.
Invasive species inflict major ecological, economic, social, and cultural harm worldwide, highlighting the urgent need for innovative and effective control strategies. Genome editing offers exciting possibilities for creating highly targeted control methods for invasive species. Here, we demonstrate CRISPR-Cas9 genome editing in the cane toad (Rhinella marina), one of Australia’s most notorious invasive species, by targeting the tyrosinase gene to produce albino phenotypes that provide clear visual markers for assessing editing efficiency. Microinjection of Cas9 protein and guide RNAs into one-cell zygotes resulted in 87.6% of mosaic larvae displaying nearly complete albinism, with 2.3% exhibiting complete albinism. For completely albino individuals, genomic analysis confirmed predominantly frameshift mutations or large deletions at the target site, with no wild-type alleles detected. Germline transmission rates reflected the extent of albinism in the mosaic adult, where we achieved maternal germline transmission rates of almost 100%. This technology, representing the first application of CRISPR-Cas9 in the Bufonidae family, opens possibilities for exploring both basic research questions and strategies for population control.
Gene editing, extinction and ethics: Why open conversation is key
34872Gabriela Harrod, ASU News, 2025-05-26 21:41:15.
In a new paper published in Science, researchers are challenging one of conservation’s deepest assumptions — that extinction is always a failure to be avoided. With new genome-editing tools making it technically possible to eliminate entire species, the question is no longer just scientific, but ethical: When, if ever, should we consider driving a species extinct on purpose? The study, titled “Deliberate extinction by genome modification: An ethical challenge,” brought together ethicists, conservation biologists, ecologists and social scientists to explore this complex question. ASU School of Life Sciences Professor James Collins co-authored the piece, which argues that while extinction should never be taken lightly, there may be “extremely rare and compelling” cases where it is justified. “This is a research area that is inherently counterintuitive,” Collins said. “At a time when biodiversity is more valued than ever, the idea that it could be ethically permissible to deliberately eradicate a species seems paradoxical. But we’re asking: Are there situations where it makes sense?” According to Gregory Kaebnick, a senior research scholar at The Hastings Center and the paper’s lead author, this conversation started over lunch during a National Academies meeting on gene drive research. Collins posed the idea that full extinction might mark an ethical line that genome-editing technologies shouldn’t cross. “The answer we offer in this new paper is, in effect, ‘almost, but not quite,’” Kaebnick said.
A Gene Drive with a Disappearing Act Can Aid Pest Control
34537Shelby Bradford, PhD, The Scientist, 2025-02-21 12:02:41.
Geneticists developed a gene drive that reverts insecticide-resistant mutations in insects, using a system that gradually eliminates itself from the genome. This breakthrough offers a potential solution to combat insecticide resistance without permanently altering species, and could be adapted to mosquitoes and other pests in the future.
Man Vs. Mosquito
33147Aman Vora, Brown Political Review, 2024-10-31 08:49:52.
It is a middle school math teacher’s favorite trivia question: What is the world’s deadliest animal? After images of a hunting tiger or towering gorilla flash through our imagination, we remember that it is the humble mosquito, whose terrible impact on human lives and healthcare systems is only projected to grow. As carbon emissions continue to rise with no plateau in sight, one oft-forgotten implication of increasing global temperatures is the devastating impact they will wreak on public health, with historically ignored diseases now able to thrive in a new, warmer climate. As global temperatures barrel toward the preferred range for mosquitoes, the number of individuals at risk for contracting malaria and dengue fever may increase by four to seven billion by 2070 relative to 1999. This threat is already a reality. Take dengue, for example: From 1980 to 1989, there were 1.5 million reported cases globally. Compare that to 2019 alone, when 5.2 million cases were reported. World Health Organization (WHO) officials described this astronomical rise in dengue as a “canary in the coalmine of the climate crisis.” No longer will mosquito-borne diseases primarily threaten equatorial regions—northern cities globally are all at risk due to the rise of Aegypti and Anopheles mosquitoes. Science: 0. Mosquitoes: 1. From bed nets to insecticides, progress is being made to combat this terrifying rise. But the current generation of anti-mosquito tools is not aggressive enough to mitigate this deadly problem: Bed nets do little to stop Aegypti, which primarily feed on blood during the day, and toxic insecticides have done little but harm the environment and drive mosquito resistance. In order to save lives from this man-made and mosquito-driven catastrophe, humanity must embrace its most promising scientific technologies: genetic engineering and Wolbachia bacteria, conscious that we are fighting against both Mother Nature and human nature itself.
The potential of gene drives in malaria vector species to control malaria in African environments
32702Hancock, P.A., North, A., Leach, A.W. et al., Nature Communications, 15. 2024-10-22 14:44:25.
Gene drives are a promising means of malaria control with the potential to cause sustained reductions in transmission. In real environments, however, their impacts will depend on local ecological and epidemiological factors. We develop a data-driven model to investigate the impacts of gene drives that causes vector population suppression. We simulate gene drive releases in sixteen ~ 12,000 km2 areas of west Africa that span variation in vector ecology and malaria prevalence, and estimate reductions in vector abundance, malaria prevalence and clinical cases. Average reductions in vector abundance ranged from 71.6–98.4% across areas, while impacts on malaria depended strongly on which vector species were targeted. When other new interventions including RTS,S vaccination and pyrethroid-PBO bednets were in place, at least 60% more clinical cases were averted when gene drives were added, demonstrating the benefits of integrated interventions. Our results show that different strategies for gene drive implementation may be required across different African settings.
To CRISPR or Not to CRISPR? Ethical Considerations in Gene-Editing Insects
31614Brendan Parent, Meghan Barrett, American Entomologist, 70:54-57. 2024-09-18 21:33:47.
Genetically modified corn has helped feed the world (Hernandes-Lopes et al. 2023). Genetically modified mosquitoes could help eliminate devastating diseases like malaria (Hammond and Galizi 2017). Plainly, gene editing can serve some important human interests. Still, many people object to it. While some concerns have little scientific validity, there are valid ethical concerns that should be addressed. A concern many people share is the potential impact of genetically edited insects on the environment. Gene drives are “selfish” genetic elements that are transmitted to progeny at unusually high rates and thus spread rapidly through populations. As a result, they are capable of modifying an entire population or species. The most widely discussed use of gene drives is in the prevention of malaria, the leading cause of human illness and death in many parts of the world (CDC 2021), where gene drives could be used to control mosquito populations. At present, however, there are no sure-fire strategies to “recall” a gene drive once it has been released (Hammond and Galizi 2017). Given the many unintended environmental impacts of other technological advancements and our uncertainties about the impacts of using gene drives (Ahmad et al. 2022), it makes sense to have similar concerns about this form of gene editing. Granted, it is possible that the extraordinary benefits to human life of such a gene drive, if successful, outweigh the risks of any unintended environmental consequences. This is particularly likely to be true if convincing measures like “terminator genes” can be employed to control genetically edited insect populations in the wild (Hammond et al. 2021). Given the serious promise and ethical concerns of this technology, the National Academy of Sciences has published guidelines for responsible research that include self-governance and government regulation, evaluating gene drives on a case-by-case basis (NASEM 2016). So, while risks of environmental harm are important, we can now see how they might not be decisive: first, the corresponding benefits might be very weighty; second, the risks might be mitigable.
Population suppression by release of insects carrying a dominant sterile homing gene drive targeting doublesex in Drosophila
34760Chen, W., Guo, J., Liu, Y. et al., Nature Communications, 15. 2024-09-14 09:17:45.
CRISPR homing gene drives can suppress pest populations by targeting female fertility genes, converting wild-type alleles into drive alleles in the germline of drive heterozygotes. fsRIDL (female-specific Release of Insects carrying a Dominant Lethal) is a self-limiting population suppression strategy involving continual release of transgenic males carrying female lethal alleles. Here, we propose an improved pest suppression system called “Release of Insects carrying a Dominant-sterile Drive” (RIDD), combining performance characteristics of homing drive and fsRIDL. We construct a split RIDD system in Drosophila melanogaster by creating a 3-gRNA drive disrupting the doublesex female exon. Drive alleles bias their inheritance in males, while drive alleles and resistance alleles formed by end-joining cause dominant female sterility. Weekly releases of RIDD males progressively suppressed and eventually eliminated cage populations. Modeling shows that RIDD is substantially stronger than SIT and fsRIDL. RIDD is also self-limiting, potentially allowing targeted population suppression.
New genetic editing technique can modify wild populations with less risk
31062Macquarie University, Phys.org, 2024-08-14 09:44:13.
A new technique developed by researchers from Macquarie University and the California Institute of Technology could allow scientists to more safely alter the genetic makeup of wild populations. The study is published in the journal Nature Communications. The researchers have proposed a new technique that aims to address some of the regulatory challenges and public concerns associated with existing genetic modification methods. Lead author Dr. Maciej Maselko from Applied Biosciences at Macquarie University says the technique, called an Allele Sail, would allow beneficial genetic changes to spread through a population without leaving "foreign DNA" behind. "Allele Sail offers a way to change the traits and fates of wild populations in ways that may be more acceptable, as the genetically modified part is introduced at low frequencies and usually won't last forever," he says. Genetic engineering could address major global challenges by altering the genetic makeup of certain wild populations—for example, to combat mosquito-borne illnesses such as malaria, or stop the spread of environmentally harmful invasive pests like cane toads. But there is genuine public concern about introducing genetic modification into wild populations, and many regulatory constraints. People are worried that modified organisms could contain foreign DNA that cause unpredictable ecological consequences over time; they worry that engineered genes could spread to other species with unknown impacts on ecosystems; and they also fear that once genetic modifications are introduced, they may not be able to be reversed. Traditional methods of genetic modification can also see a rapid spread of engineered genes within a population, raising both ecological and ethical questions. In response, many regulatory frameworks have been introduced to address genetic modification, presenting further challenges.
Chinese researchers make genetic breakthrough that could change the future of agriculture: ‘Powerful and transformative strategy’
30945Jeremiah Budin, The Cool Down, 2024-07-25 18:38:42.
Chinese scientists have reportedly engineered a way to use gene-editing technology to bypass natural plant behavior and force crops to inherit genes that will make them more resilient and easier to grow, according to Interesting Engineering. "The genetic manipulation of wild plant populations has emerged as a potentially powerful and transformative strategy," the researchers said. The technique involves using CRISPR gene-editing technology to bypass traditional Mendelian inheritance — the process by which genes are passed down through generations — to breed plants with "ideal" genes. The system is known as CRISPR-Assisted Inheritance, or CAIN. "This gene drive-based approach thus seeks to balance crop protection and environmental considerations to minimise the loss of biodiversity while optimising productivity," the researchers wrote. "As we venture into this new frontier in genetic engineering, [CAIN] and other gene drive systems could reshape ecological management and agricultural practices."
Re-engineering cancerous tumors to self-destruct and kill drug-resistant cells
30884Pennsylvania State University, Medical Xpress, 2024-07-07 21:20:02.
Treating cancer can sometimes feel like a game of Whac-A-Mole. The disease can become resistant to treatment, and clinicians never know when, where and what resistance might emerge, leaving them one step behind. But a team led by Penn State researchers has found a way to reprogram disease evolution and design tumors that are easier to treat. They created a modular genetic circuit that turns cancer cells into a "Trojan horse," causing them to self-destruct and kill nearby drug-resistant cancer cells. Tested in human cell lines and in mice as proof of concept, the circuit outsmarted a wide range of resistance. The findings were published today, July 4, in the journal Nature Biotechnology. The researchers also filed a provisional application to patent the technology described in the paper. "This idea was born out of frustration. We're not doing a bad job of developing new therapeutics to treat cancer but how can we think about potential cures for more late-stage cancers?" said Justin Pritchard, Dorothy Foehr Huck and J. Lloyd Huck Early Career Entrepreneurial Associate Professor of Biomedical Engineering and senior author on the paper. "Selection gene drives are a powerful new paradigm for evolution-guided anticancer therapy. I love the idea that we can use a tumor's inevitability of evolution against it."
Chinese scientists find natural selection loophole that could help transform food security
30867Victoria Bela, South China Morning Post, 2024-07-02 12:29:51.
Scientists in China have found a way to bypass natural plant gene inheritance, by using a CRISPR-based gene editing system to boost the transmission of preferred genes even when they are detrimental to a plant. By harnessing a system that uses both a toxin and an antidote to target the male plant germline, the scientists were able to overcome the natural Mendelian transmission rate, achieving gene transmission rates of up to 99 per cent over two generations. “Facing diverse challenges such as threats to food security from agricultural weeds and the environmental crisis of invasive plants, the genetic manipulation of wild plant populations has emerged as a potentially powerful and transformative strategy,” the team wrote in a paper published in the peer-reviewed journal Nature Plants on Monday.
Djibouti Unleashes Controversial Genetically Modified Mosquitoes
30497Palki Sharma, Firstpost, 2024-06-04 20:55:28.
Djibouti is combatting malaria by employing a unique tactic: utilising mosquitoes to battle mosquitoes. The East African nation has released tens of thousands of genetically engineered mosquitoes armed with a "self-limiting" gene. This bioengineered gene aims to curb mosquito populations by terminating their offspring. However, concerns have been voiced about the experimental nature of this genetic modification technique and the absence of adequate regulation. While Burkina Faso, Brazil, Panama, and India have ventured into similar endeavors, the efficacy and long-term implications of such interventions remain uncertain. The debate persists: are genetically modified mosquitoes a daring gamble or a promising solution to eradicate deadly diseases like malaria?
Genetically modified mosquitoes to fight malaria
30493The Naked Scientists, 2024-06-04 17:15:48.
Genetically engineered mosquitoes are taking to the air in an experiment to attempt to curtail malaria in Djibouti. The tiny African nation all but eliminated malaria just over a decade ago. But rising population and urbanisation has seen disease cases skyrocketing again, making it an ideal venue to test the technology, which uses a genetic trick to kill off selectively female mosquitoes; this leaves the males - which don’t bite humans - unharmed to breed and pass on the trait to other members of the species.
Curing mosquitoes with genetic approaches for malaria control
30356Mary Kefi, Victor Cardoso-Jaime, Sally A. Saab, George Dimopoulos, Trends in Parasitology, 2024-05-21 19:48:52.
Malaria remains a persistent global public health challenge because of the limitations of current prevention tools. The use of transgenic mosquitoes incapable of transmitting malaria, in conjunction with existing methods, holds promise for achieving elimination of malaria and preventing its reintroduction. In this context, population modification involves the spread of engineered genetic elements through mosquito populations that render them incapable of malaria transmission. Significant progress has been made in this field over the past decade in revealing promising targets, optimizing genetic tools, and facilitating the transition from the laboratory to successful field deployments, which are subject to regulatory scrutiny. This review summarizes recent advances and ongoing challenges in ‘curing’ Anopheles vectors of the malaria parasite.
Wolbachia infection-responsive immune genes suppress Plasmodium falciparum infection in Anopheles stephensi
29565Vandana V, Dong S, Sheth T, Sun Q, Wen H, Maldonado A, et al., PLoS Pathogens, 20. 2024-04-25 18:04:55.
Wolbachia, a maternally transmitted symbiotic bacterium of insects, can suppress a variety of human pathogens in mosquitoes, including malaria-causing Plasmodium in the Anopheles vector. However, the mechanistic basis of Wolbachia-mediated Plasmodium suppression in mosquitoes is not well understood. In this study, we compared the midgut and carcass transcriptomes of stably infected Anopheles stephensi with Wolbachia wAlbB to uninfected mosquitoes in order to discover Wolbachia infection-responsive immune genes that may play a role in Wolbachia-mediated anti-Plasmodium activity. We show that wAlbB infection upregulates 10 putative immune genes and downregulates 14 in midguts, while it upregulates 31 putative immune genes and downregulates 15 in carcasses at 24 h after blood-fed feeding, the time at which the Plasmodium ookinetes are traversing the midgut tissue. Only a few of these regulated immune genes were also significantly differentially expressed between Wolbachia-infected and non-infected midguts and carcasses of sugar-fed mosquitoes. Silencing of the Wolbachia infection-responsive immune genes TEP 4, TEP 15, lysozyme C2, CLIPB2, CLIPB4, PGRP-LD and two novel genes (a peritrophin-44-like gene and a macro domain-encoding gene) resulted in a significantly greater permissiveness to P. falciparum infection. These results indicate that Wolbachia infection modulates mosquito immunity and other processes that are likely to decrease Anopheles permissiveness to Plasmodium infection.
Monitoring Aedes populations for arboviruses, Wolbachia, insecticide resistance and its mechanisms in various agroecosystems in Benin
29064S. Ateutchia-Ngouanet, F. Nanfack-Minkeu, K. Mavridis, S. Wanji, M. Demanou, J. Vontas, R. Djouaka, Acta Tropica, 253. 2024-04-02 11:34:55.
The susceptibility of arbovirus vectors to insecticides and the microbiome of Aedes species are understudied in Benin.
On EAC’s GMO disharmony and little-known GM mosquito research
29025Gitura Mwaura, The New Times, 2024-03-19 13:18:15.
A meeting in Dar es Salaam in November 2022 sought to chart the legal way forward for the Target Malaria and Transmission Zero Project, as the research initiative is called.
Genome editing in pests: basic science to applications
28908Chen, X., Palli, S.R., Journal of Pest Science, 2024-02-20 15:39:21.
Recent developments in sequencing technologies produced enormous data on gene sequences and the identity of genes in many pest insects and disease vectors. However, the function of many of these genes is unknown. Functional genomics studies to uncover gene function in pest insects are urgently needed. RNA interference methods could be used in some insects but not most due to their variable efficiency among insect pests. Recently developed clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system of genome editing method is being developed for use in many insect pests. This technology has already been demonstrated to function in more than 40 insect pest species from seven orders and has contributed to advances in pest biology and the development of improved pest management methods. This review summarizes recent results of CRISPR/Cas9 technology developments and their contributions to advancing the basic and applied science of insect pests and disease vectors.
Transgenic expression of cif genes from Wolbachia strain wAlbB recapitulates cytoplasmic incompatibility in Aedes aegypti
28882McNamara, C.J., Ant, T.H., Harvey-Samuel, T. et al., Nature Communications, 15. 2024-02-13 17:43:47.
The endosymbiotic bacteria Wolbachia can invade insect populations by modifying host reproduction through cytoplasmic incompatibility (CI), an effect that results in embryonic lethality when Wolbachia-carrying males mate with Wolbachia-free females. Here we describe a transgenic system for recreating CI in the major arbovirus vector Aedes aegypti using CI factor (cif) genes from wAlbB, a Wolbachia strain currently being deployed to reduce dengue transmission. CI-like sterility is induced when cifA and cifB are co-expressed in testes; this sterility is rescued by maternal cifA expression, thereby reproducing the pattern of Wolbachia-induced CI. Expression of cifB alone is associated with extensive DNA damage and disrupted spermatogenesis. The strength of rescue by maternal cifA expression is dependent on the comparative levels of cifA/cifB expression in males. These findings are consistent with CifB acting as a toxin and CifA as an antitoxin, with CifA attenuating CifB toxicity in both the male germline and in developing embryos. These findings provide important insights into the interactions between cif genes and their mechanism of activity and provide a foundation for the building of a cif gene-based drive system in Ae. aegypti.
The $11million wasp to end (hopefully) all wasps
28867Kieran Chisnall, Stuff, 2024-01-30 20:07:32.
A new project to eradicate wasps, which cost the country millions of dollars, has begun in Dunedin. The key to that $11million project would be a genetically altered wasp, capable of destroying wasps colonies from the inside. Professor Peter Dearden, Genomics Aotearoa co-director, said: “We are using this as a test case for all New Zealand pests, a prototype for what can be done in the most ethical way, the safest way, and the way that follows the science. “What we want is to develop research to make this firstly, scientifically possible, and secondly, offer a blueprint for how it can be done, if and when New Zealand decides we want to do it.” The nationwide research led by Genomics Aotearoa began with the opening of new labs in Dunedin this week. It will be in that controlled environment where researchers will make the transgenic organism - a wasp that has been genetically modified with a flaw.
New gene-editing tools may help wipe out mosquito-borne diseases
28859Greg Allen, NPR, 2024-01-30 17:05:14.
In the age-old war of human versus mosquitoes, the bugs have been winning. At least 700,000 people die every year from mosquito-borne diseases such as malaria, dengue, West Nile and yellow fever. Global trade and climate change have helped disease-carrying species become established in places like Florida, California, and Texas. In parts of the U.S., dengue is now a persistent problem. Last year, for the first time in decades, Florida and Texas reported locally-acquired malaria cases. Maryland also had a case. But by using bioengineering, scientists have developed tools they believe may help control and possibly eradicate mosquitoes that carry dengue, malaria and other diseases. Andrea Leal, the head of mosquito control in the Florida Keys says, "The good news is we've got these emerging technologies that show great promise in reducing Aedes aegypti mosquitoes."
A multiplexed, confinable CRISPR/Cas9 gene drive can propagate in caged Aedes aegypti populations
28857Anderson, M.A.E., Gonzalez, E., Edgington, M.P. et al., Nature Communications, 15. 2024-01-30 16:38:51.
Aedes aegypti is the main vector of several major pathogens including dengue, Zika and chikungunya viruses. Classical mosquito control strategies utilizing insecticides are threatened by rising resistance. This has stimulated interest in new genetic systems such as gene drivesHere, we test the regulatory sequences from the Ae. aegypti benign gonial cell neoplasm (bgcn) homolog to express Cas9 and a separate multiplexing sgRNA-expressing cassette inserted into the Ae. aegypti kynurenine 3-monooxygenase (kmo) gene. When combined, these two elements provide highly effective germline cutting at the kmo locus and act as a gene drive. Our target genetic element drives through a cage trial population such that carrier frequency of the element increases from 50% to up to 89% of the population despite significant fitness costs to kmo insertions. Deep sequencing suggests that the multiplexing design could mitigate resistance allele formation in our gene drive system.
Gene editing would be helpful for pest control, report says
28836Alex Binkley, National Newswatch, 2024-01-23 18:28:10.
Ottawa-Canada needs to boost its gene editing research capacity to better advance that branch of science’s pest control potential, says a report by the Council of Canadian Academies. There is insufficient intensive research and development activity in gene-edited pest control in the country even though research capacity in related field exists, the report said. “Better alignment among Canada’s main public research funders is needed to develop the necessary personnel, and channel the correct expertise toward responsible technology development.” Gene editing research elsewhere is rapidly evolving and “contributes to an increasing variety of prospective mechanisms of action in genetic pest control, across numerous species.” Climate change will make pest issues more complex due to its potential impacts on ecosystems. That makes a risk assessment process central to decision-making in pest control that can be used to obtain valuable stakeholder and other input for prioritizing which technologies should be supported, the report said.
Maxizyme-mediated suppression of chikungunya virus replication and transmission in transgenic Aedes aegypti mosquitoes
28819Mishra P, Balaraman V, Fraser Jr. M, Frontiers in Microbiology, 14. 2024-01-23 14:40:52.
Chikungunya virus (CHIKV) is an emerging mosquito-borne pathogen of significant public health importance. There are currently no prophylactic vaccines or therapeutics available to control CHIKV. One approach to arbovirus control that has been proposed is the replacement of transmission-competent mosquitoes with those that are refractory to virus infection. Several transgene effectors are being examined as potentially useful for this population replacement approach. We previously demonstrated the successful use of hammerhead ribozymes (hRzs) as an antiviral effector transgene to control CHIKV infection of, and transmission by, Aedes mosquitoes. In this report we examine a maxizyme approach to enhance the catalytic activity and prevent virus mutants from escaping these ribozymes. We designed a maxizyme containing minimized (monomer) versions of two hRzs we previously demonstrated to be the most effective in CHIKV suppression. Three versions of CHIKV maxizyme were designed: Active (Mz), inactive (ΔMz), and a connected CHIKV maxizyme (cMz). The maxizymes with their expression units (Ae-tRNA val promoter and its termination signal) were incorporated into lentivirus vectors with selection and visualization markers. Following transformation, selection, and single-cell sorting of Vero cells, clonal cell populations were infected with CHIKV at 0.05 and 0.5 MOI, and virus suppression was assessed using TCID50-IFA, RT-qPCR, and caspase-3 assays. Five transgenic mosquito lines expressing cMz were generated and transgene insertion sites were confirmed by splinkerette PCR. Our results demonstrate that Vero cell clones expressing Mz exhibited complete inhibition of CHIKV replication compared to their respective inactive control version or the two parent hRzs. Upon oral challenge of transgenic mosquitoes with CHIKV, three out of the five lines were completely refractory to CHIKV infection, and all five lines tested negative for salivary transmission. Altogether, this study demonstrates that maxizymes can provide a higher catalytic activity and viral suppression than hRzs.
African scientist could wipe out malaria by editing mosquito DNA
28731Nimi Princewill, CNN, 2023-12-19 13:03:40.
Malaria is a leading cause of death in Burkina Faso, where nearly all of the West African nation’s 22 million inhabitants, especially children, are at risk of the disease, according to the World Health Organization. Malaria killed nearly 19,000 people in Burkina Faso in 2021, the most recent data from the WHO regional office for Africa showed. The disease is also one of the main causes of death in the wider African region, which shoulders the world’s largest malaria burden. Abdoulaye Diabate faced a life-threatening bout of malaria when he was just five years old. Diabate narrowly survived the mosquito-borne disease, but cousins ages three and four were not as fortunate. Diabate, who now heads medical entomology and parasitology at Burkina Faso’s Research Institute in Health Sciences, is developing an innovative technique that could potentially wipe out malaria-transmitting mosquito species by altering their genes.
CRISPR/Cas9: a cutting-edge solution for combatting the fall armyworm, Spodoptera frugiperda
28724Gouda, M.N.R., Jeevan, H., Shashank, H.G., Molecular Biology Reports, 51. 2023-12-19 12:15:58.
The utilization of CRISPR/Cas9 in Spodoptera frugiperda, commonly known as fall armyworm, presents a groundbreaking avenue for pest management. With its ability to precisely modify the insect’s genome, CRISPR/Cas9 offers innovative strategies to combat this destructive pest. The application of CRISPR/Cas9 in S. frugiperda holds immense potential. It enables the identification and functional analysis of key genes associated with its behavior, development, and insecticide resistance. This knowledge can unveil novel target sites for more effective and specific insecticides. Additionally, CRISPR/Cas9 can facilitate the development of population control methods by disrupting vital genes essential for survival. However, challenges such as off-target effects and the efficient delivery of CRISPR/Cas9 components remain. Addressing these obstacles is vital to ensure accurate and reliable results. Furthermore, ethical considerations, biosafety protocols, and regulatory frameworks must be integral to the adoption of this technology. Looking forward, CRISPR/Cas9-based gene drive systems hold the potential to promulgate desirable genetic traits within S. frugiperda populations, offering a sustainable and eco-friendly approach. This could curtail their reproductive capabilities or make them more susceptible to certain interventions. In conclusion, CRISPR/Cas9 presents a transformative platform for precise and targeted pest management in S. frugiperda. By deciphering the insect’s genetic makeup and developing innovative strategies, we can mitigate the devastating impact of fall armyworm on agriculture while ensuring environmental sustainability.
A population modification gene drive targeting both Saglin and Lipophorin impairs Plasmodium transmission in Anopheles mosquitoes
28671Emily I Green, Etienne Jaouen, Dennis Klug, Roenick Proveti Olmo, Amandine Gautier, Stéphanie Blandin, Eric Marois, eLife, 12. 2023-12-06 11:55:36.
Lipophorin is an essential, highly expressed lipid transport protein that is secreted and circulates in insect hemolymph. We hijacked the Anopheles coluzzii Lipophorin gene to make it co-express a single-chain version of antibody 2A10, which binds sporozoites of the malaria parasite Plasmodium falciparum. The resulting transgenic mosquitoes show a markedly decreased ability to transmit Plasmodium berghei expressing the P. falciparum circumsporozoite protein to mice. To force the spread of this anti-malarial transgene in a mosquito population, we designed and tested several CRISPR/Cas9-based gene drives. One of these is installed in, and disrupts, the pro-parasitic gene Saglin and also cleaves wild-type Lipophorin, causing the anti-malarial modified Lipophorin version to replace the wild type and hitch-hike together with the Saglin drive. Although generating drive-resistant alleles and showing instability in its gRNA-encoding multiplex array, the Saglin-based gene drive reached high levels in caged mosquito populations and efficiently promoted the simultaneous spread of the antimalarial Lipophorin::Sc2A10 allele. This combination is expected to decrease parasite transmission via two different mechanisms. This work contributes to the design of novel strategies to spread antimalarial transgenes in mosquitoes, and illustrates some expected and unexpected outcomes encountered when establishing a population modification gene drive.
Homing-based gene drives can introgress rapidly into local genetic backgrounds with minimal chromosomal conversion in Anopheles gambiae
28663Tony Nolan, Poppy Pescod, Giulia Bevivino et al., Research Square, 2023-12-06 10:02:37.
CRISPR-Cas9 gene drive control strategies use a homing selfish genetic element which induces a double-stranded break at the target site and is copied into the opposing chromosome, breaking an essential gene and ensuring super-Mendelian inheritance. During the copying process SNPs could potentially be transferred from one chromosome to another, converting tracts of the target to match the recipient. This would reduce the ability of gene drives to escape their genetic background of origin, with potential impacts on carrier fitness and the success of the strategy. In this study we use Anopheles gambiae strains with variation around the target site to determine the extent of chromosomal conversion during gene drive activity and the mechanism of inheritance bias. We confirm a homing-based mechanism and show that two thirds of homing events are resolved within 50 bp, showing that gene drive introgression into a wild strain can occur within one generation.
Invasive Feral Cats Could Be Wiped Out Using Genetic Modification
28632Jess Thomson, Newsweek, 2023-12-04 10:38:32.
Hordes of feral cats terrorizing native species in Australia could be combatted using a special type of genetic engineering, scientists have suggested. The cats, which came to Australia via European colonizers, regularly kill native mammals, birds, and reptiles, including woylies, quolls, and even penguins. The feral cats now number over six million, and are responsible for the extinction of at least 28 species across the country, threatening countless more. This has spurred numerous control measures to be announced, including poison, trapping, and cat curfews. "Gene drives literally 'drive' modified genes through a species by ensuring they are inherited from generation to generation, eventually resulting in the whole species having engineered genetic traits," Andrew D. Maynard, a professor of Advanced Technology Transitions at Arizona State University, told Newsweek. "It's a technique that is specific to species that mate and reproduce sexually, and works by ensuring that engineered genetic traits are inherited by every single offspring resulting from mating."
Anopheles gambiae on remote islands in the Indian Ocean: origins and prospects for malaria elimination by genetic modification of extant populations
28597Ditter, R.E., Campos, M., Crepeau, M.W. et al., Scientific Reports, 13. 2023-11-29 16:40:50.
The mosquito Anopheles gambiae s.s. is a primary malaria vector throughout sub-Saharan Africa including the islands of the Comoros archipelago (Anjouan, Grande Comore, Mayotte and Mohéli). These islands are located at the northern end of the Mozambique Channel in eastern Africa. Previous studies have shown a relatively high degree of genetic isolation between the Comoros islands and mainland populations of A. gambiae, but the origin of the island populations remains unclear. Here, we analyzed phylogenetic relationships among island and mainland populations using complete mitochondrial genome sequences of individual A. gambiae specimens. This work augments earlier studies based on analysis of the nuclear genome. We investigated the source population of A. gambiae for each island, estimated the number of introductions, when they occurred and explored evidence for contemporary gene flow between island and mainland populations. These studies are relevant to understanding historical patterns in the dispersal of this important malaria vector and provide information critical to assessing their potential for the exploration of genetic-based vector control methods to eliminate this disease. Phylogenetic analysis and haplotype networks were constructed from mitogenome sequences of 258 A. gambiae from the four islands. In addition, 112 individuals from seven countries across sub-Saharan Africa and Madagascar were included to identify potential source populations. Our results suggest that introduction events of A. gambiae into the Comoros archipelago were rare and recent events and support earlier claims that gene flow between the mainland and these islands is limited. This study is concordant with earlier work suggesting the suitability of these oceanic islands as appropriate sites for conducting field trial releases of genetically engineered mosquitoes (GEMs).
Use of Drosophila Transgenics to Identify Functions for Symbiont Effectors
28574Cortez, C.T., Murphy, R.O., Owens, I.M., Beckmann, J.F., Methods in Molecular Biology, 2739. 2023-11-29 14:35:56.
Wolbachia, one of the most successful and studied insect symbionts, and Drosophila, one of the most understood model insects, can be exploited as complementary tools to unravel mechanisms of insect symbiosis. Although Wolbachia itself cannot be grown axenically as clonal isolates or genetically manipulated by standard methods, its reproductive phenotypes, including cytoplasmic incompatibility (CI), have been elucidated using well-developed molecular tools and precise transgenic manipulations available for Drosophila melanogaster. Current research only scratches the surface of how Drosophila can provide a tool for understanding Wolbachia’s evolutionary success and the molecular roles of its genetic elements. Here, we briefly outline basic methodologies inherent to transgenic Drosophila systems that have already contributed significant advances in understanding CI, but may be unfamiliar to those who lack experience in Drosophila genetics. In the future, these approaches will continue providing significant insights into Wolbachia that undoubtedly will be extended to other insect symbionts and their biological capabilities.
Efficient sex separation by exploiting differential alternative splicing of a dominant marker in Aedes aegypti
28568Shih-Che Weng, Igor Antoshechkin, Eric Marois, Omar S. Akbari, PLoS Genetics, 2023-11-29 14:02:53.
Only female mosquitoes consume blood giving them the opportunity to transmit deadly human pathogens. Therefore, it is critical to remove females before conducting releases for genetic biocontrol interventions. Here we describe a robust sex-sorting approach termed SEPARATOR (Sexing Element Produced by Alternative RNA-splicing of A Transgenic Observable Reporter) that exploits sex-specific alternative splicing of an innocuous reporter to ensure exclusive dominant male-specific expression. Using SEPARATOR, we demonstrate reliable sex selection from early larval and pupal stages in Aedes aegypti, and use a Complex Object Parametric Analyzer and Sorter (COPAS) to demonstrate scalable high-throughput sex-selection of first instar larvae. Additionally, we use this approach to sequence the transcriptomes of early larval males and females and find several genes that are sex-specifically expressed. SEPARATOR can simplify mass production of males for release programs and is designed to be cross-species portable and should be instrumental for genetic biocontrol interventions.
Advances and challenges in synthetic biology for mosquito control
28545Shih-Che Weng, Reem A. Masri, Omar S. Akbari, Trends in Parasitology, 2023-11-28 11:40:23.
Mosquito-borne illnesses represent a significant global health peril, resulting in approximately one million fatalities annually. West Nile, dengue, Zika, and malaria are continuously expanding their global reach, driven by factors that escalate mosquito populations and pathogen transmission. Innovative control measures are imperative to combat these catastrophic ailments. Conventional approaches, such as eliminating breeding sites and using insecticides, have been helpful, but they face challenges such as insecticide resistance and environmental harm. Given the mounting severity of mosquito-borne diseases, there is promise in exploring innovative approaches using synthetic biology to bolster mosquitoes' resistance to pathogens, or even eliminate the mosquito vectors, as a means of control. This review outlines current strategies, future goals, and the importance of gene editing for global health defenses against mosquito-borne diseases.
Ghana publishes its guidelines on Genome Editing
28538Anonymous, BusinessGhana, 2023-11-28 11:06:04.
Ghana's National Biosafety Authority (NBA) has published its guidelines on Genome Editing and Gene Stacks with regards Genetically Modified Organisms (GMOs) joining Nigeria, Kenya, and Malawi, as the fourth country in Africa with the guidelines. Genome editing is an emerging and affordable biotechnology tool that has great promise to deliver high-yielding crop varieties, able to withstand various stresses such as droughts, floods, insect pests, or diseases and possessed quality traits for use as food, feed, or for processing. "Biotechnology is a fast-developing business with new trends of technologies and when the law was being passed, there was nothing like Genome editing, gene drive, or synthetic biotechnology, but we have them now."
New Techniques of Genetic Modification in Pest Control Spark Debate in Canada
28501Sandeep Kunchikor, Express Healthcare Management, 2023-11-26 09:51:07.
Scientists in Canada are urging serious discussions on the use of genetic modification as a new technique in pest control. In a recent report by the Pest Management Regulatory Agency, a branch of Health Canada that regulates pesticide use, experts argue that genetic modification could become a powerful tool as older insecticides lose their effectiveness and climate change leads to new infestations. Already, such techniques are being tested to prevent mosquitoes from spreading malaria. However, the authors of the report caution that there are many unknown variables. They claim that the consequences of releasing synthetic versions of natural organisms could be harmful and permanent.
Scientific report urges debate on genetic modification to control insect pests
28490Bob Weber, CTV News, 2023-11-18 11:21:22.
Scientists are learning to turn the genetics of insect pests against themselves, altering the genome of familiar foes in ways that give farmers and doctors new ways to fight them. The burgeoning field offers fresh hope against old scourges such as malaria. And it could provide shiny new tools as familiar insecticides lose their punch and climate change shuffles the deck. But concerns buzz the new technology like a cloud of gnats. "Genetic pest-control tools could dramatically shift our relationship with the environment, not only because of their potential impact on the ecosystem of which we are a part, but also because of their challenge to the social and cultural values that shape decisions surrounding their use," says a new report from the Council of Canadian Academies.
Single-cell profiling of Anopheles gambiae spermatogenesis defines the onset of meiotic silencing and premeiotic overexpression of the X chromosome
27624N. Page, C. Taxiarchi, D. Tonge, J. Kuburic, E. Chesters, A. Kriezis, K. Kyrou, L. Game, T. Nolan and R. Galizi, Commun Biol, 6:850. 2023-08-15 10:04:13.
Understanding development and genetic regulation in the Anopheles gambiae germline is essential to engineer effective genetic control strategies targeting this malaria mosquito vector. These include targeting the germline to induce sterility or using regulatory sequences to drive transgene expression for applications such as gene drive. However, only very few germline-specific regulatory elements have been characterised with the majority showing leaky expression. This has been shown to considerably reduce the efficiency of current genetic control strategies, which rely on regulatory elements with more tightly restricted spatial and/or temporal expression. Meiotic silencing of the sex chromosomes limits the flexibility of transgene expression to develop effective sex-linked genetic control strategies. Here, we build on our previous study, dissecting gametogenesis into four distinct cell populations, using single-cell RNA sequencing to define eight distinct cell clusters and associated germline cell-types using available marker genes. We reveal overexpression of X-linked genes in a distinct cluster of pre-meiotic cells and document the onset of meiotic silencing of the X chromosome in a subcluster of cells in the latter stages of spermatogenesis. This study provides a comprehensive dataset, characterising the expression of distinct cell types through spermatogenesis and widening the toolkit for genetic control of malaria mosquitoes.
The boundary problem: Defining and delineating the community in field trials with gene drive organisms
25098N. de Graeff, I. Pirson, R. van der Graaf, A. L. Bredenoord and K. R. Jongsma, Bioethics, 2023-05-03 10:11:03.
Despite widespread and worldwide efforts to eradicate vector-borne diseases such as malaria, these diseases continue to have an enormous negative impact on public health. For this reason, scientists are working on novel control strategies, such as gene drive technologies (GDTs). As GDT research advances, researchers are contemplating the potential next step of conducting field trials. An important point of discussion regarding these field trials relates to who should be informed, consulted, and involved in decision-making about their design and launch. It is generally argued that community members have a particularly strong claim to be engaged, and yet, disagreement and lack of clarity exist about how this "community" should be defined and delineated. In this paper, we shed light on this "boundary problem": the problem of determining how boundaries of inclusion and exclusion in (GDT) community engagement should be drawn. As our analysis demonstrates, the process of defining and delineating a community is itself normative. First, we explicate why it is important to define and delineate the community. Second, we demonstrate that different definitions of community are used and intermingled in the debate on GDTs, and argue in favor of distinguishing geographical, affected, cultural, and political communities. Finally, we propose initial guidance for deciding who should (not) be engaged in decision-making about GDT field trials, by arguing that the definition and delineation of the community should depend on the rationale for engagement and that the characteristics of the community itself can guide the effective design of community engagement strategies.
In The Face Of Nigerian Mosquito Nets, Westerners’ Gene Editing Offers Hope
24964O. Onwumere, The Nigerian Voice, 2023-04-10 10:42:21.
In Nigeria, the utilization of mosquito nets is prevalent, while in the Western world, optimism is associated with the implementation of gene editing technology. In this article, ODIMEGWU ONWUMERE reports that malaria could soon be eradicated in Nigeria. According to US scientists, Anopheles mosquitoes have been genetically modified to resist the malaria-causing parasite by incorporating various anti-malaria molecules that target different stages of the parasite's lifecycle. Nevertheless, the article highlights a lack of information on the knowledge and overall viewpoint of Nigerian scientists concerning GMMs
DIPA-CRISPR gene editing in the yellow fever mosquito <em>Aedes aegypti</em> (Diptera: Culicidae)
24960S. Yu, T. Momoyo, O. Manabu, K. Hirotaka and D. Takaaki, bioRxiv, 2023.04.07.535996. 2023-04-07 10:28:04.
Current methods for gene editing in insects rely on embryonic microinjection, which can be challenging for non-specialist laboratories. Recently, an alternative method known as direct parental CRISPR (DIPA-CRISPR) was developed. This method involves injecting commercial Cas9 protein and single-guide RNA into adult females, which can efficiently introduce mutations into developing oocytes. However, its versatility has not been fully explored, particularly in insects that have the most derived, polytrophic meroistic ovaries. In this study, we successfully applied DIPA-CRISPR to the yellow fever mosquito Aedes aegypti, which has polytrophic meroistic ovaries. Following adult injection of Cas9 ribonucleoproteins (Cas9 RNPs) targeting the kynurenine 3-monooxygenase gene, we recovered gene-edited G0 individuals. Injection at 24 h after blood-feeding resulted in the highest gene editing efficiency (3.5%), confirming that a key parameter of DIPA-CRISPR is the stage in which the adult females are injected. Together with our previous study, we demonstrated that DIPA-CRISPR is applicable to all three types of insect ovaries (i.e., panoistic, telotrophic, and polytrophic), which indicates that DIPA-CRISPR is a generalizable approach for insect gene editing.Competing Interest StatementThe authors have declared no competing interest.
Introducing Emerging Health Technologies in Africa
24724Health Tech Africa, Health Tech Africa Podcast, 2023-02-08 14:22:59.
In this episode, the Project Director of the Platform for Dialogue and Action on Health Technologies in Africa, Professor Richard Mukabana, discusses new technologies that if well developed and proven safe and effective, have enormous potential to eradicate disease on the continent.
Social justice environmental activists move to block gene editing to control invasive species and promote biodiversity. Here’s why they’re misguided
24701S. Smyth, Genetic Literacy Project, 2023-02-07 12:46:02.
Control of invasive species has been extremely difficult with eradication virtually impossible. To control invasive plant species, chemicals are commonly used while in some instances removal of plants by hand, as Shiva advocates, is undertaken. Efforts to control invasive animals include poisoning and shooting. Needless to say, these ‘control techniques’ are inefficient and often harmful to the applicators. Advances in genetics potentially offer new solutions, using gene editing technology to create sterile populations. Sterility is a natural trait in mammals, which can be induced into invasive animals as a means of population control. Invasive pests can be captured, gene-edited to confer sterility in future generations and then released back into the wild. The offspring will gradually without the use of chemicals or hand labor contribute to reduced populations. Applying gene editing technologies is not an instantaneous solution, but they may be part of a long-term strategy.
Control of Aedes mosquito populations using recombinant microalgae expressing short hairpin RNAs and their effect on plankton
24615X. Fei, S. Xiao, X. Huang, Z. Li, X. Li, C. He, Y. Li, X. Zhang and X. Deng, PLOS Neglected Tropical Diseases, 17:e0011109. 2023-01-26 09:15:48.
New biocontrol strategies are urgently needed to combat vector-borne infectious diseases. This study presents a low-cost method to produce a potential mosquito insecticide that utilizes the microalgae released into suburban water sources to control mosquito populations. Chlorella microalgae are ubiquitous in local waters, which were chosen as the host for genetic transfection. This species facilitated the recombinant algae to adapt to the prevailing environmental conditions with rapid growth and high relative abundance. The procedure involved microalgae RNAi-based insecticides developed using short hairpin RNAs targeting the Aedes aegypti chitin synthase A (chsa) gene in Chlorella. These insecticides effectively silenced the chsa gene, inhibiting Aedes metamorphosis in the laboratory and simulatedfield trials. This study explored the impact of recombinant microalgae on the phytoplankton and zooplankton in suburban waters. High-throughput sequencing revealed that rapid reproduction of recombinant Chlorella indirectly caused the disappearance of some phytoplankton and reduced the protozoan species. This study demonstrated that a recombinant microalgae-based insecticide could effectively reduce the population of Aedes mosquitoes in the laboratory and simulated field trials. However, the impact of this technology on the environment and ecology requires further investigation.
Gene editing and agrifood systems
24291FAO, FAO, 2022-12-20 09:22:56.
Gene-editing technologies represent a promising new tool for plant and animal breeding in low- and middle-income countries. They enhance precision and efficiency over current breeding methods and could lead to rapid development of improved plant varieties and animal breeds. However, as for any new technology, they have their merits and demerits. There is, as yet, no international consensus regarding if and how gene-edited organisms should be regulated, and whether their release would fall under the regulatory framework of the Cartagena Protocol on Biosafety to the Convention on Biological Diversity. This science- and evidence-based Issue Paper on gene editing and agrifood systems presents a balanced discussion of the most pertinent aspects of gene editing, including the consequences for human hunger, human health, food safety, effects on the environment, animal welfare, socioeconomic impact and distribution of benefits. Intrinsic ethical concerns and issues of governance and regulation are addressed, and the roles of the public and private sectors, alone and in partnership, are summarized. Various scenarios are also presented for how gene editing might be used in the future to help transform agrifood systems.
Gene drive technologies: navigating the ethical landscape
24074N. d. Graeff, Utrecht University, 2022-11-04 10:41:56.
Gene drives are technologies that modify a particular genetic element in animals or insects so that this genetic element does not follow the typical rules of heredity, and is passed onto future generations with an increased likelihood. Gene drive technologies could be used to tackle intractable problems such as vector-borne diseases like malaria or the biodiversity impact of invasive species. At the same time, the development and governance of gene drives raise a range of ethical questions and concerns that warrant proactive ethical evaluation. In the PhD thesis ?Gene drive technologies: navigating the ethical landscape?, Nienke de Graeff analyzes these questions and concerns. In Part I, she outlines the ?ethical landscape? of gene drive technologies by identifying the associated ethical challenges through literature review and empirical ethical research. Important challenges concern how the uncertainty and risks of these technologies should be navigated, whether it is morally permissible to intervene in nature in this way, and how the development, governance, and potential deployment of gene drive technologies should be guided. In Part II, De Graeff normatively analyzes various of these challenges and provides guidance to navigate them. In Part III, she stipulates recommendations for researchers and policymakers in the gene drive field as well as lessons learned for ethics parallel research as an approach for early ethical guidance of new and emerging technologies more generally.
Combining transgenesis with paratransgenesis to fight malaria
23802W. Huang, J. Vega-Rodriguez, C. Kizito, S.-J. Cha and M. Jacobs-Lorena, eLife, 11:e77584. 2022-10-25 06:30:55.
Malaria is among the deadliest infectious diseases, and Plasmodium, the causative agent, needs to complete a complex development cycle in its vector mosquito for transmission to occur. Two promising strategies to curb transmission are transgenesis, consisting of genetically engineering mosquitoes to express antimalarial effector molecules, and paratransgenesis, consisting of introducing into the mosquito commensal bacteria engineered to express antimalarial effector molecules. Although both approaches restrict parasite development in the mosquito, it is not known how their effectiveness compares. Here we provide an in-depth assessment of transgenesis and paratransgenesis and evaluate the combination of the two approaches. Using the Q-system to drive gene expression, we engineered mosquitoes to produce and secrete two effectors – scorpine and the MP2 peptide – into the mosquito gut and salivary glands. We also engineered Serratia, a commensal bacterium capable of spreading through mosquito populations to secrete effectors into the mosquito gut. Whereas both mosquito-based and bacteria-based approaches strongly reduced the oocyst and sporozoite intensity, a substantially stronger reduction of Plasmodium falciparum development was achieved when transgenesis and paratransgenesis were combined. Most importantly, transmission of Plasmodium berghei from infected to naïve mice was maximally inhibited by the combination of the two approaches. Combining these two strategies promises to become a powerful approach to combat malaria.
Toward product-based regulation of crops
23498F. Gould, R. M. Amasino, D. Brossard, C. R. Buell, R. A. Dixon, J. B. Falck-Zepeda, M. A. Gallo, K. E. Giller, L. L. Glenna, T. Griffin, D. Magraw, C. Mallory-Smith, K. V. Pixley, E. P. Ransom, D. M. Stelly and C. N. Stewart, Science, 377:1051-1053. 2022-09-02 19:04:01.
Current process-based approaches to regulation are no longer fit for purpose Much effort has been expended globally over the past four decades to craft and update country-specific and multinational safety regulations that can be applied to crops developed by genetic engineering processes, while exempting conventionally bred crops. This differentiation made some sense in the 1980s, but in light of technological advances, it is no longer scientifically defensible. In the coming decades, innovations in genetic engineering and modern ?conventional? processes of crop development will enable use of these approaches to alter more crops and more traits. Future governance of new plant varieties and foods, regardless of the processes and techniques used to develop them, will require new, scientifically sound assessment methodologies, developed in a manner acceptable to society. Here, we provide a rationale for one governance approach that moves away from current process-based regulation and uses newly developed molecular techniques that enable detailed characterization of the new crops and foods themselves.
CRISPR-Mediated Genome Engineering in Aedes aegypti
23209R. Sun, M. Li, C. J. McMeniman and O. S. Akbari, piRNA: Methods and Protocols, 2022-07-01 06:21:38.
CRISPR-mediated genome engineering technologies have been adapted to a wide variety of organisms with high efficiency and specificity. The yellow fever mosquito, Aedes aegyptiAedes aegypti, is one such organism. It is also responsible for transmitting a wide variety of deadly viruses including Dengue, Zika, Yellow fever, and Chikungunya. The key to successful CRISPR-mediated gene editingGene editing applications is the delivery of both Cas9 ribonuclease and single-guide RNA (sgRNASingle guide RNA (sgRNA)) to the nucleus of desired cells. Various methods have been developed for supplying the Cas9 endonuclease, sgRNASingle guide RNA (sgRNA), and donor DNA to Ae. aegypti. In this chapter, we focus on methods of direct embryoEmbryosdelivery of editing components, presenting detailed step-by-step CRISPR/Cas9-based genome-editing protocols for inducing desired heritable edits in mosquitoes as well as insights into successful application of these protocols. We also highlight potential opportunities for customizing these protocols to manipulate the mosquito genome for innovative in vivoIn vivo gene function studies.
The suppressive potential of a gene drive in populations of invasive social wasps is currently limited
23091A. B. Meiborg, N. R. Faber, B. A. Taylor, B. A. Harpur and G. Gorjanc, bioRxiv, 2022.06.27.497711. 2022-06-30 07:33:43.
Social insects are very successful invasive species, and the continued increase of global trade and transportation has exacerbated this problem. The yellow-legged hornet, Vespa velutina nigrithorax (henceforth Asian hornet), is drastically expanding its range in Western Europe. As an apex insect predator, this hornet poses a serious threat to the honey bee industry and endemic pollinators. Current suppression methods have proven too inefficient and expensive to limit its spread. Gene drives might be an effective tool to control this species, but their use has not yet been thoroughly investigated in social insects. Here, we built a model that matches the hornet’s life history and modelled the effect of different gene drive scenarios on an established invasive population. To test the broader applicability and sensitivity of the model, we also incorporated the invasive European paper wasp Polistes dominula. We find that although a gene drive can spread through a social wasp population, it can only do so under stringent gene drive-specific conditions. The main issue is that the large number of offspring that social wasp colonies produce guarantees that, even with very limited formation of resistance alleles, such alleles will quickly spread and rescue the population. Furthermore, we find that only a gene drive targeting female fertility is promising for population control due to the haplodiploidy of social insects. Nevertheless, continued improvements in gene drive technology may make it a promising method for the control of invasive social insects.Competing Interest StatementThe authors have declared no competing interest.
Gene Editing and Genetic Control of Hemipteran Pests: Progress, Challenges and Perspectives
22757I. D. Pacheco, L. L. Walling and P. W. Atkinson, Frontiers in Bioengineering and Biotechnology, 10. 2022-06-07 08:02:11.
The origin of the order Hemiptera can be traced to the late Permian Period more than 230 MYA, well before the origin of flowering plants 100 MY later in during the Cretaceous period. Hemipteran species consume their liquid diets using a sucking proboscis; for phytophagous hemipterans their mouthparts (stylets) are elegant structures that enable voracious feeding from plant xylem or phloem. This adaptation has resulted in some hemipteran species becoming globally significant pests of agriculture resulting in significant annual crop losses. Due to the reliance on chemical insecticides for the control of insect pests in agricultural settings, many hemipteran pests have evolved resistance to insecticides resulting in an urgent need to develop new, species-specific and environmentally friendly methods of pest control. The rapid advances in CRISPR/Cas9 technologies in model insects such as Drosophila melanogaster, Tribolium castaneum, Bombyx mori, and Aedes aegypti has spurred a new round of innovative genetic control strategies in the Diptera and Lepidoptera and an increased interest in assessing genetic control technologies for the Hemiptera. Genetic control approaches in the Hemiptera have, to date, been largely overlooked due to the problems of introducing genetic material into the germline of these insects. The high frequency of CRISPR-mediated mutagenesis in model insect species suggest that, if the delivery problem for Hemiptera could be solved, then gene editing in the Hemiptera might be quickly achieved. Significant advances in CRISPR/Cas9 editing have been realized in nine species of Hemiptera over the past 4 years. Here we review progress in the Hemiptera and discuss the challenges and opportunities for extending contemporary genetic control strategies into species in this agriculturally important insect orderr.
What role can gene editing play in predator control? And are we ready to accept it?
22727K. Green, Stuff, 2022-05-16 08:07:14.
The once-forbidden concept of gene editing for predator control is back on the table after two projects receivedGovernment funding. Despite advances overseas, experts are worried research in New Zealand will never make it out of the lab, with no plans to change current restrictive laws. Appetite for gene editing has always been low among the New Zealand public. In 1999, 20,000 people protested in Auckland alone, marching down Auckland’s Queen St calling for a ban on genetically engineered crops. Gene editing joined nuclear-free as a hallmark of clean, green New Zealand. However last month, the crown entity responsible for pest control, Predator Free 2050, announced investment of $6.7 million into research projects, including $2.25m to investigate whether recent overseas advances in producing mice of only one sex could be adapted for rats, and $200,000 to explore stoat breeding genetics, and whether that could be used for control.
Recent advancements in CRISPR/Cas technology for accelerated crop improvement
21827D. Das, D. L. Singha, R. R. Paswan, N. Chowdhury, M. Sharma, P. S. Reddy and C. Chikkaputtaiah, Planta, 255:109. 2022-04-25 09:34:49.
The likelihood of reduced agricultural production due to highly turbulent climatic conditions increases as the global population expands. The second paradigm of stress-resilient crops with enhanced tolerance and increased productivity against various stresses is paramount to support global production and consumption equilibrium. Although traditional breeding approaches have substantially increased crop production and yield, effective strategies are anticipated to restore crop productivity even further in meeting the world’s increasing food demands. CRISPR/Cas, which originated in prokaryotes, has surfaced as a coveted genome editing tool in recent decades, reshaping plant molecular biology in unprecedented ways and paving the way for engineering stress-tolerant crops. CRISPR/Cas is distinguished by its efficiency, high target specificity, and modularity, enables precise genetic modification of crop plants, allowing for the creation of allelic variations in the germplasm and the development of novel and more productive agricultural practices. Additionally, a slew of advanced biotechnologies premised on the CRISPR/Cas methodologies have augmented fundamental research and plant synthetic biology toolkits. Here, we describe gene editing tools, including CRISPR/Cas and its imitative tools, such as base and prime editing, multiplex genome editing, chromosome engineering followed by their implications in crop genetic improvement. Further, we comprehensively discuss the latest developments of CRISPR/Cas technology including CRISPR-mediated gene drive, tissue-specific genome editing, dCas9 mediated epigenetic modification and programmed self-elimination of transgenes in plants. Finally, we highlight the applicability and scope of advanced CRISPR-based techniques in crop genetic improvement.
Overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors
21579N. A. Ratcliffe, J. P. Furtado Pacheco, P. Dyson, H. C. Castro, M. S. Gonzalez, P. Azambuja and C. B. Mello, Parasites and Vectors, 15:112. 2022-03-31 12:47:27.
This article presents an overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors. It first briefly summarises some of the disease-causing pathogens vectored by insects and emphasises the need for innovative control methods to counter the threat of resistance by both the vector insect to pesticides and the pathogens to therapeutic drugs. Subsequently, the state of art of paratransgenesis is described, which is a particularly ingenious method currently under development in many important vector insects that could provide an additional powerful tool for use in integrated pest control programmes. The requirements and recent advances of the paratransgenesis technique are detailed and an overview is given of the microorganisms selected for genetic modification, the effector molecules to be expressed and the environmental spread of the transgenic bacteria into wild insect populations. The results of experimental models of paratransgenesis developed with triatomines, mosquitoes, sandflies and tsetse flies are analysed. Finally, the regulatory and safety rules to be satisfied for the successful environmental release of the genetically engineered organisms produced in paratransgenesis are considered.
The power of gene editing
20973The Economist, The Economist, 2022-03-17 07:27:42.
Technologies such as genetic modification and ‘CRISPR’ will cure hereditary diseases, produce disease-resistant crops and enable the breeding of malaria-free mosquitos. But advances bring ethical and practical dilemmas. Genetically modified food is banned in the EU, and doctors worry that screening for genetic diseases may pave the way for more controversial uses, such as creating so-called designer babies. This film looks at the risks and rewards of gene editing.
First ever gene-edited ticks offer new weapons against Lyme disease
20524N. Lavars, New Atlas, 2022-02-16 08:14:12.
Gene editing in ticks had been thought to be impossible until now, and with good reason. Tick embryos are very tricky to inject because the egg that contains them has a tough layer on the outside, high pressure levels inside, and is also coated in a waxy layer the mothers create using what's called the Gené's organ."Despite their capacity to acquire and pass on an array of debilitating pathogens, research on ticks has lagged behind other arthropod vectors, such as mosquitoes, largely because of challenges in applying available genetic and molecular tools," said Monika Gulia-Nuss, a co-senior author of the study and a molecular biologist at the University of Nevada, Reno. Gulia-Nuss and her research team, which included scientists from the University of Maryland and Penn State University, believe they have finally cracked the code. The first step in the breakthrough technique involves ablating the Gené's organ to prevent the formation of the waxy coating. The eggs were then treated with chemicals benzalkonium chloride and sodium chloride to both eliminate the tough protective layer and lower the pressure inside the eggs.
Insect Allies – Assessment of a Viral Approach to Plant Genome Editing
20036K. Pfeifer, J. L. Frieß and B. Giese, Integrated Environmental Assessment and Management, 2022-01-12 09:38:06.
The DARPA program Insect Allies has already sparked scientific debate concerning technology assessment-related issues, among which the most prevalent is that of dual use potential. As apart from the issues concerning peaceful applications, the technology also provides the blueprint for a potential bioweapon as further evidenced by a recent publication. However, the combination of a virus-induced genetic modification of crop plants in the field using genetically modified insect vectors poses an increased risk potential in comparison to the hitherto existing use of genetically modified organisms. The technology's high depth of intervention enables a number of sources for hazard and a by trend high exposure, but it is also encumbered with notable deficits in knowledge. These issues call for a thorough technology assessment. This article aims to provide an initial characterization from a technology assessment perspective, focusing on potential sources of risk for this novel invasive environmental biotechnology at an early stage of research and development. This article is protected by copyright. All rights reserved.© 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
Gene Editing in the Wild: Shaping Decisions through Broad Public Deliberation
19701M. K. Gusmano, G. E. Kaebnick, K. J. Maschke, C. P. Neuhaus and B. C. Wills, The Hastings Center Report, 51. 2021-12-14 19:46:28.
The essays in this special report grew out of a project funded by the National Science Foundation (with NSF award number 1827935). Gregory E. Kaebnick and Michael K. Gusmano were co-principal investigators on the project, and Karen J. Maschke and Carolyn P. Neuhaus were coinvestigators. Ben Curran Wills was project manager and research assistant. Genetic editing technologies have long been used to modify domesticated nonhuman animals and plants. Recently, attention and funding have also been directed toward projects for modifying nonhuman organisms in the shared environment—that is, in the “wild.” Interest in gene editing nonhuman organisms for wild release is motivated by a variety of goals, and such releases hold the possibility of significant, potentially transformative benefit. The technologies also pose risks and are often surrounded by a high uncertainty. Given the stakes, scientists and advisory bodies have called for public engagement in the science, ethics, and governance of gene editing research in nonhuman organisms. Most calls for public engagement lack details about how to design a broad public deliberation, including questions about participation, how to structure the conversations, how to report on the content, and how to link the deliberations to policy. We summarize the key design elements that can improve broad public deliberations about gene editing in the wild.
Deficits of Public Deliberation in U.S. Oversight for Gene Edited Organisms
19650J. Kuzma, Hastings Center Report, 51 Suppl 2:S25-s33. 2021-12-14 18:49:23.
Environmental releases of gene edited (GEdOs) and gene drive organisms (GDOs) will likely occur under conditions of high uncertainty and in complex socioecological systems. Therefore, public deliberation is especially important to account for diverse interpretations of safety, risks, and benefits; to draw on experiential and public wisdom in areas of proposed release; to ameliorate dangers of technological optimism; and to increase the public legitimacy of decisions. Yet there is a "democratic deficit" in the United States' oversight system for GEdOs and GDOs, as unconflicted experts, publics, and skeptical stakeholders are most often excluded from decision-making and unavailable to critically examine potential risks and benefits or raise broader concerns about socioeconomic or cultural impacts. This article argues for the need to open up decision-making for GEdOs and GDOs, discusses the challenges for doing so within the current oversight framework, and finally, proposes institutional, policy, and attitudinal changes that are likely important for overcoming barriers to public deliberation.
Public Deliberation about Gene Editing in the Wild
19648M. K. Gusmano, G. E. Kaebnick, K. J. Maschke, C. P. Neuhaus and B. C. Wills, Hastings Center Report, 51 Suppl 2:S2-s10. 2021-12-14 18:42:52.
Genetic editing technologies have long been used to modify domesticated nonhuman animals and plants. Recently, attention and funding have also been directed toward projects for modifying nonhuman organisms in the shared environment-that is, in the "wild." Interest in gene editing nonhuman organisms for wild release is motivated by a variety of goals, and such releases hold the possibility of significant, potentially transformative benefit. The technologies also pose risks and are often surrounded by a high uncertainty. Given the stakes, scientists and advisory bodies have called for public engagement in the science, ethics, and governance of gene editing research in nonhuman organisms. Most calls for public engagement lack details about how to design a broad public deliberation, including questions about participation, how to structure the conversations, how to report on the content, and how to link the deliberations to policy. We summarize the key design elements that can improve broad public deliberations about gene editing in the wild.
The Decision Phases Framework for Public Engagement: Engaging Stakeholders about Gene Editing in the Wild
19643S. K. Barnhill-Dilling, A. Kokotovich and J. A. Delborne, Hastings Center Report, 51 Suppl 2:S48-s61. 2021-12-14 18:30:37.
Some experts and advocates propose environmental biotechnologies such as genetic engineering, gene drive systems, and synthetic biology as potential solutions to accelerating rates of species loss. While these tools may offer hope for a seemingly intractable problem, they also present potential governance challenges for which innovative decision-making systems are required. Two of the perennial governance challenges include, when are broader stakeholder groups involved in these decisions and who exactly should be involved? We propose the decision phases framework-which includes research and development, regulatory review, and deployment, management, and monitoring-as a framework for identifying which stakeholders might be best suited for different phases throughout the innovation and deployment of emerging environmental biotechnologies for species protection.
Public Perceptions Regarding Genomic Technologies Applied to Breeding Farm Animals: A Qualitative Study
19920F. Z. Naab, D. Coles, E. Goddard and L. J. Frewer, BioTech, 10. 2021-12-03 09:13:38.
The societal acceptability of different applications of genomic technologies to animal production systems will determine whether their innovation trajectories will reach the commercialisation stage. Importantly, technological implementation and commercialisation trajectories, regulation, and policy development need to take account of public priorities and attitudes. More effective co-production practices will ensure the application of genomic technologies to animals aligns with public priorities and are acceptable to society. Consumer rejection of, and limited demand for, animal products developed using novel genomic technologies will determine whether they are integration into the food system. However, little is known about whether genomic technologies that accelerate breeding but do not introduce cross-species genetic changes are more acceptable to consumers than those that do. Five focus groups, held in the north east of England, were used to explore the perceptions of, and attitudes towards, the use of genomic technologies in breeding farm animals for the human food supply chain. Overall, study participants were more positive towards genomic technologies applied to promote animal welfare (e.g., improved disease resistance), environmental sustainability, and human health. Animal “disenhancement” was viewed negatively and increased food production alone was not perceived as a potential benefit. In comparison to gene editing, research participants were most negative about genetic modification and the application of gene drives, independent of the benefits delivered.
Genome editing and its applications for insect pest control: Curse or blessing?
19401Hacker, I. , and Schetelig, M. F, AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 18:00:39.
Gene and genome editing are described as cutting-edge research tools with the potential to tackle urgent global challenges in the management of agricultural pests and human disease vectors such as mosquitoes. The field is defined by the chances and challenges to interlink the disciplines of insect genomics, molecular biology, and pest control together with the need for clear risk assessment, policy development and public approval of the application of such novel technologies. The goal is to generate innovative and sustainable pest control solutions applied in the best interest for the environment and human society. Here, starting from available genome editing technologies, the current strategies and applications for insect pest control are discussed, including approaches to overcome the evolution of resistance alleles and other potential pitfalls to be expected from selective pressures resulting from gene drive applications. They are supplemented by views on regulatory, policy and ethical considerations that in our opinion will be necessary to define how the different tools can be used in the future in a safe and responsible way.
Procedurally Robust Risk Assessment Framework for Novel Genetically Engineered Organisms and Gene Drives
19376Kuzma, J., Regulation and Governance, 15:1144-1165. 2021-11-29 17:13:52.
In this article, a new framework for improving risk assessments of novel genetically engineered organisms (GEOs) is developed and applied. The Procedurally Robust Risk Assessment Framework (PRRAF) provides a set of principles and criteria for assessing and enhancing risk assessment protocols for GEOs under conditions of high uncertainty. The application of PRRAF is demonstrated using the case of a genetically engineered mosquito designed to kill its wild population and therefore decrease disease transmission. Assessments for regulatory approval of this genetically engineered insect fall short of several PPRAF criteria under the principles of humility, procedural validity, inclusion, anticipation, and reflexivity. With the emergence of GEOs designed to spread in ecosystems, such as those with gene drives, it will become increasingly important for regulatory agencies and technology developers to bolster their risk analysis methods and processes prior to field testing. PRRAF can be used as a flexible guide for doing so within a variety of institutional, regulatory, and governance contexts.
Genome Editing Tools and Gene Drives: A Brief Overview (1st ed.).
19295R. Mudziwapasi, R. Chekera, C. Z. Ncube, I. Shoko, B. Ncube, T. Moyo, J. G. Chimbo, J. Dube, F. F. Mashiri, M. A. Mubani, D. Maruta, C. Chimbo, M. Masuku, R. Shoko, R. P. Nyamusamba and F. N. Jomane, CRC Press, 2021-10-21 14:20:34.
Genome-editing methods are becoming routine tools for molecular and cell biologists. Such tools include ZFNs, CRISPR, megaTALs and TALENs. These tools are revolutionizing the creation of precisely manipulated genomes to modify the characteristics of organisms or cells. Additionally, gene drives have altered the way we understand inheritance laws. They give us the ability to have total control of the inheritance of traits of choice and importance. This succinct volume summarizes the history, principles and applications – as well as the advantages and disadvantages – of each of these tools and various kinds of gene drives. The book is part of a program to produce books helpful to students and faculties of science at colleges and universities. This volume in the Pocket Guides to Biomedical Sciences series will help demystify these technologies. The book fills the gap between established conventional methods and the novel and exciting newly introduced tools of genome editing and gene drives. It will help young scientists understand the emerging genome-editing tools and gene drives, thereby promoting related research and adoption.
Gene drive: a faster route to plant improvement
18859H. A. Siddiqui, T. Harvey-Samuel and S. Mansoor, Trends in Plant Science, 2021-10-06 18:24:37.
Gene drives for control of vector-borne diseases have been demonstrated in insects but remain challenging in plants. Theoretically, they could be transformative in speeding breeding programs and contributing to food security through providing novel weed control methods. Zhang et al. now report the possibility of implementing gene drive in plants for the first time.
Genetically Modified Mosquitoes — What’s The Real Story?
18289SPW Staff, Southeast Product Weekly, 2021-09-02 14:58:32.
You’ve heard about the genetically modified mutant mosquitoes being released in the Florida Keys — but what exactly is going on, and how, and why? Basically, researchers in parts of the Florida Keys are releasing male mosquitoes that have been genetically modified to produce only male offspring. In a generation or two, there are no more girl mosquitoes to have baby mosquitoes. That’s the simple explanation. t might help to know this experiment was tried once before — successfully — in Brazil.There’s now a new, science-based online information resource about genetically modified mosquitoes from University of Florida scientists at the UF/IFAS Florida Medical Entomology Laboratory. “Genetically Modified Mosquitoes” is the latest publication on Ask IFAS, UF/IFAS’ Electronic Data Information Source (EDIS) peer-reviewed site, that provides relevant information regarding the pilot projects in select areas of the Florida Keys. The experiments, which are a collaboration between the Florida Keys Mosquito Control District and the biotechnology company Oxitec founded in the United Kingdom out of Oxford University, are permitted by the U.S. Environmental Protection Agency (EPA).
Mosquito transgenesis for malaria control
18284S. Dong, Y. Dong, M. L. Simões and G. Dimopoulos, Trends in Parasitology, 2021-09-02 14:42:32.
Malaria is one of the deadliest diseases. Because of the ineffectiveness of current malaria-control methods, several novel mosquito vector-based control strategies have been proposed to supplement existing control strategies. Mosquito transgenesis and gene drive have emerged as promising tools for preventing the spread of malaria by either suppressing mosquito populations by self-destructing mosquitoes or replacing mosquito populations with disease-refractory populations. Here we review the development of mosquito transgenesis and its application for malaria control, highlighting the transgenic expression of antiparasitic effector genes, inactivation of host factor genes, and manipulation of miRNAs and lncRNAs. Overall, from a malaria-control perspective, mosquito transgenesis is not envisioned as a stand-alone approach; rather, its use is proposed as a complement to existing vector-control strategies.
UF/IFAS Researchers Explain Science Behind Genetically Modified Mosquitoes
18276PCT Staff, Pest Control Technology, 2021-09-01 14:14:47.
South Florida residents seeking science-based information about genetically modified mosquitoes can access a new, online resource from University of Florida scientists at the UF/IFAS Florida Medical Entomology Laboratory.“ Genetically Modified Mosquitoes” is the latest publication on Ask IFAS, UF/IFAS’ Electronic Data Information Source (EDIS) peer-reviewed site, that provides relevant information regarding the pilot projects in select areas of the Florida Keys. The experiments, which are a collaboration between the Florida Keys Mosquito Control District and the biotechnology company Oxitec founded in the United Kingdom out of Oxford University, are permitted by the U.S. Environmental Protection Agency (EPA). The UF/IFAS publication describes the mosquito species being targeted, what to expect from the pilot projects, why this approach is being used as well as answers to other frequently asked questions about genetically modified mosquitoes. The publication also lists additional linked resources for readers interested in more detailed information on the topic and science. “The rationale for producing this document is to help inform the public and those who are interested or impacted by the current trials run by Oxitec,” said Eric Caragata, an assistant professor at UF/IFAS FMEL. “As scientists who are not directly involved in the project, we wanted to clearly address some of the important questions and concerns.”
Versatile Applications of the CRISPR/Cas Toolkit in Plant Pathology and Disease Management
19445M. S. Wheatley and Y. N. Yang, Phytopathology, 111:1080-1090. 2021-08-25 21:11:15.
New tools and advanced technologies have played key roles in facilitating basic research in plant pathology and practical approaches for disease management and crop health. Recently. the CRISPR/Cas (clustered regularly interspersed short palindromic repeats/CRISPR-associated) system has emerged as a powerful and versatile tool for genome editing and other molecular applications. This review aims to introduce and highlight the CRISPR/Cas toolkit and its current and future impact on plant pathology and disease management. We will cover the rapidly expanding horizon of various CRISPR/Cas applications in the basic study of plant-pathogen interactions, genome engineering of plant disease resistance, and molecular diagnosis of diverse pathogens. Using the citrus greening disease as an example, various CRISPR/Cas-enabled strategies are presented to precisely edit the host genome for disease resistance, to rapidly detect the pathogen for disease management, and to potentially use gene drive for insect population control. At the cutting edge of nucleic acid manipulation and detection, the CRISPR/Cas toolkit will accelerate plant breeding and reshape crop production and disease management as we face the challenges of 21st century agriculture.
Cas9-Mediated Gene-Editing in the Black-Legged Tick, Ixodes Scapularis, by Embryo Injection and ReMOT Control.
17197A. a. P. Sharma, Michael N. and Reyes, Jeremiah B. and Chana, Randeep and Yim, Won C. and Heu, Chan C. and Kim, Donghun and Chaverra-Rodriguez, Duverney and Rasgon, Jason L. and Harrell, Robert A. and Nuss, Andrew B. and Gulia-Nuss, Monika,, Cell Reports, 2021-08-20 20:35:08.
Despite their capacity to acquire and pass on an array of debilitating pathogens, research on ticks has lagged behind other arthropod vectors, such as mosquitoes, largely because of a lack of genetic and molecular tools. CRISPR-Cas9 is transforming non-model organism research; however, successful gene editing has not yet been reported in ticks. Technical challenges for injecting tick embryos to attempt gene editing have further slowed research progress. Herein we report a successful tick embryo injection protocol for the black-legged tick, Ixodes scapularis, the first for any chelicerate species, and the use of this protocol for genome editing with CRISPR-Cas9. We also demonstrated for the first time that the ReMOT Control technique can be successfully used to generate genome mutations outside Insecta. Our results provide innovative tools to the tick research community that are essential for advancing our understanding of the molecular mechanisms governing pathogen transmission by tick vectors as well as for understanding the underlying biology of host-vector-pathogen interactions.
Genetically Modified Mosquitoes
18286E. P. Caragata, Y. Lee and E. A. Buckner, UF IFAS Extension Service, 2021-08-17 14:49:18.
Genetically modified (GM) mosquitoes are controversial, partly because of misinformation. This publication provides science-based information about GM mosquitoes to the public and anyone involved in mosquito control. It explains what GM mosquitoes are and why they are being investigated as a tool for mosquito control. Describes a GM mosquito pilot project in Florida, and includes FAQs and answers explaining how GM mosquitoes are created and their potential impacts on people and the environment.
Sustainable Food Production: The Contribution of Genome Editing in Livestock
17590A. Menchaca, Sustainability, 13. 2021-06-21 13:52:55.
This article is focused on the scope and perspectives for the application of this technology, which includes improving production traits, enhancing animal welfare through adaptation and resilience, conferring resistance to infectious diseases, and suppressing pests and invasive species that threaten livestock. The main advantages and concerns that should be overcome by science, policy and people are discussed with the aim that this technology can make a real contribution to our collective future. This review is part of the special issue “Genome Editing in Animal Systems to Support Sustainable Farming and Pest Control”.
New CRISPR Tools Can Help Contain Mosquito Disease Transmission
17191Anonymous, labcompare, 2021-06-01 20:26:34.
Scientists have now developed several genetic editing tools that help pave the way to an eventual gene drive designed to stop Culex mosquitoes from spreading disease. As detailed in the journal Nature Communications, Xuechun Feng, Valentino Gantz and their colleagues at Harvard Medical School and National Emerging Infectious Diseases Laboratories developed a Cas9/guide-RNA expression "toolkit" designed for Culex mosquitoes. Since such little attention in genetic engineering has been devoted to Culex mosquitoes, the researchers were required to develop their toolkit from scratch, starting with a careful examination of the Culex genome. While Culex mosquitoes are less problematic in the United States, they are much more of a health risk in Africa and Asia, where they transmit the worm causing filariasis, a disease that can lead to a chronic debilitating condition known as elephantiasis. The researchers also demonstrated that their tools could work in other insects.
Researchers Create New CRISPR Tools to Help Contain Mosquito Disease Transmission
18225M. Aguilera, UC San Diego News Center, 2021-05-28 15:43:14.
Much less genetic engineering has been devoted to Culex genus mosquitoes, which spread devastating afflictions stemming from West Nile virus—the leading cause of mosquito-borne disease in the continental United States—as well as other viruses such as the Japanese encephalitis virus (JEV) and the pathogen causing avian malaria, a threat to Hawaiian birds.University of California San Diego scientists have now developed several genetic editing tools that help pave the way to an eventual gene drive designed to stop Culex mosquitoes from spreading disease. Gene drives are designed to spread modified genes, in this case those that disable the ability to transmit pathogens, throughout the targeted wild population.As detailed in the journal Nature Communications, Xuechun Feng, Valentino Gantz and their colleagues at Harvard Medical School and National Emerging Infectious Diseases Laboratories developed a Cas9/guide-RNA expression “toolkit” designed for Culex mosquitoes. Since such little attention in genetic engineering has been devoted to Culex mosquitoes, the researchers were required to develop their toolkit from scratch, starting with a careful examination of the Culex genome.
New CRISPR tools help contain mosquito disease transmission: Genetics toolkit targets less researched Culex mosquitoes, which transmit West Nile virus and avian malaria.
17145University of California - San Diego, ScienceDaily, 2021-05-28 13:29:00.
Since the onset of the CRISPR genetic editing revolution, scientists have been working to leverage the technology in the development of gene drives that target pathogen-spreading mosquitoes such as Anopheles and Aedes species, which spread malaria, dengue and other life-threatening diseases. Much less genetic engineering has been devoted to Culex genus mosquitoes, which spread devastating afflictions stemming from West Nile virus -- the leading cause of mosquito-borne disease in the continental United States -- as well as other viruses such as the Japanese encephalitis virus (JEV) and the pathogen causing avian malaria, a threat to Hawaiian birds. University of California San Diego scientists have now developed several genetic editing tools that help pave the way to an eventual gene drive designed to stop Culex mosquitoes from spreading disease. Gene drives are designed to spread modified genes, in this case those that disable the ability to transmit pathogens, throughout the targeted wild population.
Optimized CRISPR tools and site-directed transgenesis towards gene drive development in Culex quinquefasciatus mosquitoes
17147X. Feng, V. López Del Amo, E. Mameli, M. Lee, A. L. Bishop, N. Perrimon and V. M. Gantz, Nature Communications, 12:2960. 2021-05-20 13:34:20.
Culex mosquitoes are a global vector for multiple human and animal diseases, including West Nile virus, lymphatic filariasis, and avian malaria, posing a constant threat to public health, livestock, companion animals, and endangered birds. While rising insecticide resistance has threatened the control of Culex mosquitoes, advances in CRISPR genome-editing tools have fostered the development of alternative genetic strategies such as gene drive systems to fight disease vectors. However, though gene-drive technology has quickly progressed in other mosquitoes, advances have been lacking in Culex. Here, we develop a Culex-specific Cas9/gRNA expression toolkit and use site-directed homology-based transgenesis to generate and validate a Culex quinquefasciatus Cas9-expressing line. We show that gRNA scaffold variants improve transgenesis efficiency in both Culex quinquefasciatus and Drosophila melanogaster and boost gene-drive performance in the fruit fly. These findings support future technology development to control Culex mosquitoes and provide valuable insight for improving these tools in other species.
Genetic Manipulation of Ticks: A Paradigm Shift in Tick and Tick-Borne Diseases Research
17164A. Nuss, A. Sharma and M. Gulia-Nuss, Frontiers in Cellular and Infection Microbiology, 11:7. 2021-05-02 19:18:28.
Ticks are obligate hematophagous arthropods that are distributed worldwide and are one of the most important vectors of pathogens affecting humans and animals. Despite the growing burden of tick-borne diseases, research on ticks has lagged behind other arthropod vectors, such as mosquitoes. This is largely because of challenges in applying functional genomics and genetic tools to the idiosyncrasies unique to tick biology, particularly techniques for stable genetic transformations. CRISPR-Cas9 is transforming non-model organism research; however, successful germline editing has yet to be accomplished in ticks. Here, we review the ancillary methods needed for transgenic tick development and the use of CRISPR/Cas9, the most promising gene-editing approach, for tick genetic transformation.
Introduction of a cold sensitivity-conferring mutation into the RTA-Bddsx hybrid system of Bactrocera dorsalis for establishment of a thermally controllable homozygous line
17327S. M. Dai, C. Y. Huang and C. Chang, Pest Management Science, 7. 2021-04-10 14:40:01.
BACKGROUND For efficient control of the economically important fruit pest Bactrocera dorsalis, a hybrid system combining ricin toxicity and sex-related alternative splicing of the doublesex gene has been developed. This system exhibits the expected female-specific lethal effect; however, the transgenic females do not survive, making it difficult to raise stable homozygous lines. Since modification of ricin toxin A chain (RTA) through a single-residue change (Gly(212) > Arg(212)) leads to cold-sensitive posttranslational repression of its toxicity, we utilized this unique property to obtain RTA-Bddsx females that survive at low temperature for line maintenance. RESULTS In transient expression experiments using embryonic injection, two groups treated with RTAcs-derived DNA (LERQcs and RTAcs) exhibited temperature-dependent effects. The toxicity was higher at 29 degrees C than at 18 degrees C. The proportion of males was close to 50% at 18 degrees C in all the tested groups except LERQcs-treated flies, which exhibited a high proportion of males (over 70%) at 29 degrees C. The results indicate the cold-sensitive responses of RTA and further suggest a female-specific lethal effect. Subsequently, 14 putative RTAcs-Bddsx transgenic Ds-Red(+) G(1) males were identified, and female-specific lethal effects were observed in Ds-Red(+) G(2) and G(3) lines under cultivation at 29 degrees C but not at 18 degrees C. The male ratio can be increased to up to 95% in G(3) line 001, indicating that RTAcs functions well in B. dorsalis. CONCLUSION The improved RTAcs-Bddsx system with conditional toxicity represents a novel and promising step toward the practical control of B. dorsalis.
CRISPR-mediated knock-in of transgenes into the malaria vector Anopheles funestus
16674C. Quinn, A. Anthousi, C. Wondji and T. Nolan, bioRxiv, 2021.03.31.437891. 2021-03-31 13:57:08.
We describe herein an optimised transformation system based on the germline delivery of CRISPR components that allows efficient cleavage of a previously validated genomic site and preferential repair of these cut sites via homology-directed repair (HDR), which allows introduction of exogenous template sequence, rather than end-joining repair. The rates of transformation achieved are sufficiently high that it should be able to introduce alleles of choice to a target locus, and recover these, without the need to include additional dominant marker genes. Moreover, the high rates of HDR observed suggest that gene drives, which employ an HDR-type mechanism to ensure their proliferation in the genome, may be well suited to work in An. funestus.Competing Interest StatementThe authors have declared no competing interest.
Ethics of Genome Editing
16622European Group on Ethics, European Group on Ethics in Science and New Technologies, 2021-03-19 18:16:09.
This Opinion addresses the profound ethical questions raised and revived by them. It analyses various domains of application, from human health to animal experimentation, from livestock breeding to crop variety and to gene drives. With its wide view across areas, it identifies underlying and overarching issues that deserve our concerted attention, among them, the different meanings that ought to be attributed to humanness, naturalness or diversity. This enables conclusions that provide panoramic perspectives complementing narrower, area-specific analyses. In the same vein, the Opinion is concerned with the global dimension of genome editing and its regulation and formulates recommendations with a particular focus on the international level.
Genetically Encoded CRISPR components Yield Efficient Gene Editing in the Invasive Pest, Drosophila suzukii
16602N. P. Kandul, E. J. Belikoff, J. Liu, A. Buchman, F. Li, A. Yamamoto, T. Yang, I. Shriner, M. J. Scott and O. Akbari, bioRxiv, 2021.03.15.435483. 2021-03-16 18:28:51.
Here we have developed transgenic strains that encode three different terminators and four different promoters to express Cas9 in both the soma and/or germline of SWD. The Cas9 lines were evaluated through genetic crossing to transgenic lines that encode single guide RNAs targeting the conserved X-linked yellow body and white eye genes. We find that several Cas9/gRNA lines display very high editing capacity. Going forward, these tools will be instrumental for evaluating gene function in SWD and may provide tools useful for the development of new genetic strategies for control of this invasive species.
New Pesticides Will Modify Insect Genes: What Could Go Wrong?
16587Food Tank, EcoWatch, 2021-03-09 19:44:05.
Farmers across the U.S. could soon fill their pesticide spray tanks with a substance known as interfering RNA (RNAi). (RNA is a molecule similar to DNA.) Insects that are exposed to it — either by eating crops sprayed with the substance or by landing on a crop and absorbing it through their bodies — would be genetically modified right there in the field. The pesticide would trigger a process inside the insects' cells to switch off or "silence" genes that are essential for survival — like those needed to make new, healthy cells — thus killing them.
femaleless Controls Sex Determination and Dosage Compensation Pathways in Females of Anopheles Mosquitoes
16910E. Krzywinska, L. Ferretti, J. Li, J.-C. Li, C.-H. Chen and J. Krzywinski, Current Biology, 31:1084-1091.e4. 2021-03-08 18:07:47.
Here we show that in the African malaria mosquito Anopheles gambiae, a gene, which likely arose in the Anopheles lineage and which we call femaleless (fle), controls sex determination in females by regulating splicing of dsx and fruitless (fru; another terminal gene within a branch of the sex determination pathway). Moreover, fle represents a novel molecular link between the sex determination and dosage compensation pathways. It is necessary to suppress activation of dosage compensation in females, as demonstrated by the significant upregulation of the female X chromosome genes and a correlated female-specific lethality, but no negative effect on males, in response to fle knockdown. This unexpected property, combined with a high level of conservation in sequence and function in anopheline mosquitoes, makes fle an excellent target for genetic control of all major vectors of human malaria.
Genetically modified mosquitoes for better health
16527D. Devis, COSMOS, 2021-03-04 18:24:41.
One method of preventing these mosquito-born diseases is to use insecticides to kill the mozzies and remove them, but sometimes this only works as a short term solution, or has unintended devasting effects on the ecosystem. Another method for decreasing the number of disease-carrying mozzies is to introduce disease resistant, genetically modified mozzies. These transgenic mozzies could be part of a gene drive system where they have a newly introduced disease-resistant gene, linked up with CRISPR mechanisms that help the gene dominate in the population by continuing to copy itself through the genome. All of this requires very thorough risk assessment.
Quantifying the risk of vector-borne disease transmission attributable to genetically modified vectors
16530G. R. Hosack, A. Ickowicz and K. R. Hayes, Royal Society Open Science, 8:201525. 2021-03-03 18:28:51.
The relative risk of disease transmission caused by the potential release of transgenic vectors, such as through sterile insect technique or gene drive systems, is assessed with comparison with wild-type vectors. The probabilistic risk framework is demonstrated with an assessment of the relative risk of lymphatic filariasis, malaria and o'nyong'nyong arbovirus transmission by mosquito vectors to human hosts given a released transgenic strain of Anopheles coluzzii carrying a dominant sterile male gene construct. Harm is quantified by a logarithmic loss function that depends on the causal risk ratio, which is a quotient of basic reproduction numbers derived from mathematical models of disease transmission. The basic reproduction numbers are predicted to depend on the number of generations in an insectary colony and the number of backcrosses between the transgenic and wild-type lineages. Analogous causal risk ratios for short-term exposure to a single cohort release are also derived. These causal risk ratios were parametrized by probabilistic elicitations, and updated with experimental data for adult vector mortality. For the wild-type, high numbers of insectary generations were predicted to reduce the number of infectious human cases compared with uncolonized wild-type. Transgenic strains were predicted to produce fewer infectious cases compared with the uncolonized wild-type.
Population genomics of invasive rodents on islands: Genetic consequences of colonization and prospects for localized synthetic gene drive
16657K. P. Oh, A. B. Shiels, L. Shiels, D. V. Blondel, K. J. Campbell, J. R. Saah, A. L. Lloyd, P. Q. Thomas, F. Gould, Z. Abdo, J. R. Godwin and A. J. Piaggio, Evolutionary Applications, 2021-02-22 17:41:41.
Here we used pooled whole-genome sequencing of invasive mouse (Mus musculus) populations on four islands along with paired putative source populations to test genetic predictions of island colonization and characterize locally fixed Cas9 genomic targets. Patterns of variation across the genome reflected marked reductions in allelic diversity in island populations and moderate to high degrees of differentiation from nearby source populations despite relatively recent colonization. Locally fixed Cas9 sites in female fertility genes were observed in all island populations, including a small number with multiplexing potential. In practice, rigorous sampling of presumptive LFA will be essential to fully assess risk of resistance alleles. These results should serve to guide development of improved, spatially limited gene drive design in future applications.
Emergent challenges for CRISPR: biosafety, biosecurity, patenting, and regulatory issues
19398Braddick, D. , and Ramarohetra, R. F., Genome Engineering Via Crispr-Cas9 System, 2021-02-18 17:46:33.
The recent advancements of CRISPR-Cas technologies have transformed this simple and efficient gene editing technique into an extraordinarily powerful tool. The most anticipated applications could create novel therapeutics against mankind's most serious afflictions and help eradicate vector-based diseases. However, with these desired benefits come new ethical questions and potential threats. CRISPR technologies are not yet fully developed toward delivering all of their promises, and suffer from biosafety problems in human products and biosecurity threats arising from its potential dual use and errant gene drives. Furthermore, the future innovations of CRISPR technologies may encounter non-scientific challenges in patentability and unclear legal regulations at the national and international levels. This chapter will discuss these issues, and where possible, will highlight the currently proposed solutions that could mitigate the threats, and could address the problems that hold back CRISPR's full potential.
Optimized CRISPR tools and site-directed transgenesis in Culex quinquefasciatus mosquitoes for gene drive development
16372X. Feng, V. Lopez Del Amo, E. Mameli, M. Lee, A. L. Bishop, N. Perrimon and V. M. Gantz, bioRxiv, 2021.02.10.430702. 2021-02-11 20:33:00.
Here, we developed a Culex-specific Cas9/gRNA expression toolkit and used site-directed homology-based transgenesis to generate and validate a Culex quinquefasciatus Cas9-expressing line. We showed that gRNA scaffold variants improve transgenesis efficiency in both Culex and Drosophila and boost gene-drive performance in the fruit fly. These findings support future technology development to control Culex mosquitoes and provide valuable insight for improving these tools in other species.
Assisting Evolution: How Far Should We Go to Help Species Adapt?
16369E. Kolbert, YaleEnvironment360, 2021-02-09 20:28:55.
It was a hot, intensely blue day in the Australian Outback, about 350 miles north of Adelaide. I was tagging along with Moseby as she checked the batteries on the motion-sensitive cameras that dot Arid Recovery, an ecosystem restoration project she and her husband launched in 1997. The project sprawls over 47 square miles of red earth and scrub. It’s entirely surrounded by a six-foot-tall fence, which is designed to keep out feral cats and foxes. Inside the main fence is a series of smaller fenced-in paddocks. Several years ago, Moseby decided to start adding cats into some of these. Her reasoning was simple and, in its own way, radical. The outback ecosystem had been so fundamentally changed, that, if the native animals were to survive, they would have to change, too. Perhaps they could be trained to avoid cats, which were introduced to the country by the British colonists and now can be found virtually everywhere in Australia, including most islands.
Should we dim the sun? Will we even have a choice
16384E. Klein, New York Times, 2021-02-09 15:06:18.
“Under a White Sky” is going to be on my best books of 2021 list. It’s a wonderful work. Kolbert is the Pulitzer Prize-winning author of “The Sixth Extinction,” which you may have read. She is a staff writer at The New Yorker and just one of the great science journalists of this time, and particularly one of the great climate journalists of this age. But this book, this book’s existence is evidence of how badly that fight is going. This is a book about what we are going to need to contemplate in the coming years that we don’t want to. It’s a book about taking responsibility for how irreversibly we have altered the natural world; how often we have tried to control it, and then watched those attempts at control fail; how often the best most scientific minds of the age have come up with some brilliant solution, implemented it, and then watched calamity result. And at the same time — and this is what makes the book so worthwhile — it is a book about how there is no going back. Not now, not ever. We are in the Anthropocene. The future from here is an endless layering on of new efforts to control the consequences of our past efforts. We don’t get to flinch or pretend we don’t have to contemplate any of this. We’ve gone too far. One of the hardest things to do as a writer — and I tell you this from personal experience — is to write ambivalence. It’s easy to write a polemic or a sharp take. It is hard to write down the middle path, where you are simply describing things as they are, knowing that every possible obvious answer you can come to is probably a bad one, knowing that the hubris embedded in past attempts to solve this problem means any future brilliant idea is likely to end that way, too, but that doesn’t mean we can do nothing. But Kolbert walks that path really beautifully here, which is why I wanted to talk to her for the show. As always, my email is [email protected]. I’m always interested to know who you’d like to see on the show. The weirder, the better. So send me your guest suggestions. Here’s Elizabeth Kolbert.
In Our Image: The Ethics of CRISPR Genome Editing
16272J. C. Eissenberg, Biomolecular Concepts, 12:1-7. 2021-02-06 16:55:38.
Here, I discuss the ethics surrounding the transformative CRISPR/Cas9mediated genome editing technology in the contexts of human genome editing to eradicate genetic disease and of gene drive technology to eradicate animal vectors of human disease.
Mosquitoes genetically modified to be resistant to Zika
16259Staff, Lab+Life Scientist, 2021-02-02 15:55:50.
Researchers have wrestled with different strategies for controlling the spread of Zika virus, which is transmitted to humans from female mosquito bites. One approach, which has been approved by the US Environmental Protection Agency, will see more than 750 million genetically modified mosquitoes released into the Florida Keys in 2021 and 2022. These ‘suicide mosquitoes’ are genetically altered to produce offspring that die before emerging into adults and therefore cannot bite humans and spread disease.
RNAi-based products: A sustainable alternative to hazardous pesticides
16211Ghent University, Phys Org, 2021-01-27 13:59:48.
RNAi-based biocontrol is a great alternative to hazardous pesticides and can contribute towards reversing the alarming decline in farmland birds and beneficial insects (especially pollinating ones). RNAi is a well-known natural biological process in most
Genetically-modified mosquitoes key to stopping Zika virus spread
16208University of Missouri, Medical Xpress, 2021-01-26 13:52:44.
Alexander Franz, an associate professor in the MU College of Veterinary Medicine, collaborated with researchers at Colorado State University by using CRISPR gene-editing technology to produce mosquitoes that are unable to replicate Zika virus and therefore cannot infect a human through biting. "We genetically manipulated these mosquitoes by inserting an artificial gene into their genome that triggers one of the immune pathways in the midgut to recognize and destroy the RNA genome of Zika virus," Franz said. "By developing these mosquitoes that are resistant to the virus, the disease cycle is interrupted so transmission to humans can no longer take place." Franz added that the genetic modification is inheritable, so future generations of the altered mosquitoes would be resistant to Zika virus as well.
The Antiviral Small-Interfering RNA Pathway Induces Zika Virus Resistance in Transgenic Aedes aegypti
15482A. E. Williams, I. Sanchez-Vargas, W. R. Reid, J. Y. Lin, A. W. E. Franz and K. E. Olson, Viruses, 12:18. 2020-12-15 14:45:29.
We used CRISPR/Cas9 to re-target a previously characterized locus (Chr2:321382225) and engineered mosquitoes expressing an inverted repeat (IR) dsRNA against the NS3/4A region of the ZIKV genome. Small RNA analysis revealed that the IR effector triggered the mosquito's siRNA antiviral pathway in bloodfed females. Nearly complete (90%) inhibition of ZIKV replication was found in vivo in both midguts and carcasses at 7 or 14 days post-infection (dpi). Furthermore, significantly fewer transgenic mosquitoes contained ZIKV in their salivary glands (p = 0.001), which led to a reduction in the number of ZIKV-containing saliva samples as measured by transmission assay. Our work shows that Ae. aegypti innate immunity can be co-opted to engineer mosquitoes resistant to ZIKV.
A patent review on strategies for biological control of mosquito vector
15377K. Parihar, M. Telang and A. Ovhal, World Journal of Microbiology and Biotechnology, 36:23. 2020-12-09 20:28:33.
This paper presents a comprehensive technology overview of patent documents disclosing biological agents for mosquito control. The patent analysis revealed that comparable number of patent documents were filed in two technology categories: non-recombinant agents and genetically modified (GM) agents. In the category of non-recombinant agents, toxic peptides from microbes and biological consortia seemed to be the earliest technology noted right from the year 1965 whereas the patent filings for suppression of mosquito population using genetic modification techniques have emerged from the year 2000 onwards. The United States of America is the leading patent filing jurisdiction followed by China and the Great Britain. Academic institutes have filed higher number of patent applications as compared to private companies. University of Florida was found to be the leading patent filing entity and its patents were focused on suppression of vector population using techniques such as release of insects with dominant lethal (RIDL) and RNA interference (RNAi).
Genetically Engineered Fish: Potential Impacts on Aquaculture, Biodiversity, and the Environment
15290R. A. Dunham and B. Su, GMOs: Implications for Biodiversity Conservation and Ecological Processes, 2020-12-02 17:03:48.
Studies on transgenic fish for the aquaculture industry have focused on improving growth rates, enhancing disease resistance, altering body composition, acting as biological factories for medical proteins, and even altering temperature tolerance and coloration. The future impact of transgenesis will likely be quite large. Growth hormone-transgenic salmon has been approved for human consumption and has been introduced to the market in Canada and soon to the USA. This is the first human consumption of approved transgenic meat. Transgene insertion has many pleiotropic effects. Several studies have projected the fitness of transgenic fish to be low, in general, compared to non-transgenic and wild fish; thus, their environmental risk is likely low and they would have minimal, if any, long-term impact on ecosystems or biodiversity. However, there have been no actual escapements; thus, only projections of risk are available based on small-scale experiments and the characteristics of transgenic fish compared to controls. An active area of research is repressible transgenic sterilization and sterilization using gene editing, both of which would allow application of transgenic fish with only short-term consequences for ecosystems in the worst-case scenario. Transgenic technology could also be potentially used to reduce or eliminate populations of nuisance species.
Mosquito transgenics and courtship songs
14824H. Hurd, BugBitten BMC, 2020-10-23 17:38:45.
As a female flies into the swarm she is detected by the sound of her wing beat and males identify females by a phonotactic response to the specific sound frequency produced by her wing beat. A male and female will then attune to each other by altering the frequency of their wingbeats in a form of reciprocal tuning that is highly specific.
WHO Refers to GM Mosquitoes as Beneficial Technology
14820ISAAA, Crop Biotech Update, 2020-10-21 17:27:43.
The World Health Organization (WHO) released its official statement to clarify its stance on the evaluation and use of genetically modified (GM) mosquitoes and its use to control vector-borne diseases (VBD). WHO says it supports the investigation of all potentially beneficial technologies, and these include GM mosquitoes.
Position of ARRIGE Scientific Committee on Gene Drive
14801ARRIGE Scientific Committee on Gene Drive, ARRIGE Newsletter, 2020-10-21 15:16:40.
We are facing a change of paradigm that must lead us to be responsible for altered inheritance and the hybridization between artefacts, considered as natural or artificial, at the very moment when this division itself is blurred by the engineering capacity to act on mutations, without knowing in advance the possibly adverse, short or long term, side effects, on the manipulated and other connected species.
Genetic engineering and bacterial pathogenesis against the vectorial capacity of mosquitoes
14721M. Qasim, H. M. Xiao, K. He, M. A. A. Omar, F. L. Liu, S. Ahmed and F. Li, Microbial Pathogenesis, 147:8. 2020-10-16 18:16:01.
Here we aimed to focus on the role of bacterial pathogenesis and molecular tactics for the management of mosquitoes and their vectorial capacity.
Global citizen deliberation on genome editing
14607J. S. Dryzek, D. Nicol, S. Niemeyer, S. Pemberton, N. Curato, A. Bächtiger, P. Batterham, B. Bedsted, S. Burall, M. Burgess, G. Burgio, Y. Castelfranchi, H. Chneiweiss, G. Church, M. Crossley, J. de Vries, M. Farooque, M. Hammond, B. He, R. Mendonça, J., Science, 369:1435. 2020-09-18 18:32:40.
Here we show how, as the global governance vacuum is filled, deliberation by a global citizens' assembly should play a role, for legitimate and effective governance.
Maintenance management and eradication of established aquatic invaders
13936D. Simberloff, Hydrobiologia, 22. 2020-08-06 13:34:15.
The rapid development of technologies based on genetics has engendered excitement about possibly eradicating or controlling terrestrial invaders, and such technologies may also prove useful for certain aquatic invaders. Methods of particular interest, alone or in various combinations, are gene-silencing, RNA-guided gene drives, and the use of transgenes.
How do you make a gene drive mosquito?
13053GeneConvene Virtual Institute, GeneConvene Global Collaborative, 2020-07-17 14:10:32.
This short video explains and illustrates how transgenic mosquitoes are made in the laboratory. While mosquitoes are the focus of the video, the process shown is used to create transgenic insects of almost any species.
Genome Editing in Food and Farming: Risks and unexpected consequences
13186J. Cotter and D. Perls, Canadian Biotechnology Action Network, 2020-07-14 17:53:41.
J. Cotter and D. Perls (2020). Canadian Biotechnology Action Network. In this report, we provide an overview of genome editing techniques being explored in agriculture, and the range of potential unexpected effects that can arise from them. The report draws on recent scientific publications, in a rapidly evolving field of research including gene drive and genetic biocontrol.
Socrates Untenured: Ethics, Experts, and the Public in the Synthetic Age
13182C. Preston, ISSUES in Science and Technology, 2020-07-14 17:44:20.
C. Preston (2020). Three tools have transformed biotechnology over the past decade and a half. Gene reading has made it possible to quickly sequence the genome of any living creature. Gene synthesis has made it possible to construct DNA sequences in the lab from constituent chemicals. Gene editing has made it possible to place those sections into an existing DNA sequence at any point a technician chooses.
Genome Editing 2020: Ethics and Human Rights in Germline Editing in Humans and Gene Drives in Mosquitoes
13198G. J. Annas, American Journal of Law and Medicine, 46:143-165. 2020-07-12 18:17:19.
G. J. Annas (2020). American Journal of Law and Medicine. doi: 10.1177/0098858820933492. I begin with a discussion of so far disastrously unsuccessful attempts to regulate germline editing in humans, including a summary of the first application of germline genome editing in humans and its aftermath. I then turn to a discussion of setting ethical standards for a genomic technology that has not yet been deployed in nature—gene drives. Finally, I end by suggesting that human rights can and should be directly applicable to defining the ethics of genomic research.
RNAi: Applications in Vertebrate Pest Management
14854K. E. Horak, Trends in Biotechnology, 38:1200-1202. 2020-05-25 17:42:08.
the development of novel control technologies must be focused on species specificity and low environmental impact. Sequence-specific gene silencing via RNAi holds promise for effective management of pest wildlife.
Bioethical issues in genome editing by CRISPR-Cas9 technology
11216F. B. Ayanoglu, A. E. Elcin and Y. M. Elcin, Turkish Journal of Biology, 44:110-120. 2020-04-02 15:13:15.
Genome editing technologies have led to fundamental changes in genetic science. Among them, CRISPR-Cas9 technology particularly stands out due to its advantages such as easy handling, high accuracy, and low cost. It has made a quick introduction in fields related to humans, animals, and the environment, while raising difficult questions, applications, concerns, and bioethical issues to be discussed. Most concerns stem from the use of CRISPR-Cas9 to genetically alter human germline cells and embryos (called germline genome editing). Germline genome editing leads to serial bioethical issues, such as the occurrence of undesirable changes in the genome, from whom and how informed consent is obtained, and the breeding of the human species (eugenics). However, the bioethical issues that CRISPR-Cas9 technology could cause in the environment, agriculture and livestock should also not be forgotten. In order for CRISPR-Cas9 to be used safely in all areas and to solve potential issues, worldwide legislation should be prepared, taking into account the opinions of both life and social scientists, policy makers, and all other stakeholders of the sectors, and CRISPR-Cas9 applications should be implemented according to such legislations. However, these controls should not restrict scientific freedom. Here, various applications of CRISPR-Cas9 technology, especially in medicine and agriculture, are described and ethical issues related to genome editing using CRISPR-Cas9 technology are discussed. The social and bioethical concerns in relation to human beings, other organisms, and the environment are addressed.
Auditing preparedness for vector control field studies
11210C. M. Collins and M. M. Quinlan, American Journal of Tropical Medicine and Hygiene, 102:707-710. 2020-04-01 14:52:00.
The value of baseline entomological data to any future area-wide release campaign relies on the application of consistent methods to produce results comparable across different times and places in a stepwise progression to larger releases. Traditionally, standard operating procedures (SOPs) and operational plans support this consistency and, thus, the validity of emergent data. When release plans include transgenic mosquitoes for vector control or other novel beneficial insects, additional factors come into play such as biosafety permits, stakeholder acceptance, and ethics approval, which require even greater coordination and thoroughness. An audit approach was developed to verify the correct use of SOPs and appropriate performance of tasks during mosquito mark, release, recapture (MRR) studies. Audit questions matched SOPs, permit terms and conditions, and other key criteria, and can be used to support subsequent “spot check” verification by field teams. An external team of auditors, however, was found to be effective for initial checks in this example before the use of a transgenic strain of laboratory mosquitoes. We recommend similar approaches for field studies using release of novel beneficial insects, to ensure useful and valid data as an outcome and to support confidence in the rigor of the step-wise process.
Genome engineering in insects: focus on the CRISPR/Cas9 system
19405Hillary, V. Edwin Ceasar, Stanislaus Antony Ignacimuthu, S., Genome Engineering via CRISPR-Cas9 System, 2020-02-18 18:07:54.
Genome engineering is a precise tool used to alter the genome of desired organism. Zinc finger nuclease (ZFN), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR), and the CRISPR-associated RNA guided endonuclease Cas9 (CRISPR/Cas9) are the major genome engineering tools used in these days. CRISPR/Cas9 system has redeemed the precise genome engineering in different species including insects. This chapter covers the details on genome engineering studies reported in various insects including mosquitoes, butterflies, silkworm and fruit fly with a focus on CRISPR/Cas9 system. Many studies have been reported on application of ZFN, TALEN and CRISPR/Cas9 in insects. In recent years, many scientists have adopted CRISPR/Cas9 system for insect genome modification due to its affordability and quick designing of the constructs. We also discuss the details and applications of gene drive. Further studies with CRISPR/Cas9in insects will help researchers to find an effective strategy to combat the vector borne diseases spread by insects like mosquitoes.
Engineering Bugs, Resurrecting Species: The Wild World of Synthetic Biology for Conservation
7242P. Rejcek, Singularity Hub, 2020-02-02 15:56:24.
Imagine a world where a mosquito bite is just an itchy annoyance. No malaria. No dengue fever. Last month, scientists announced they had taken one more step toward that vision. A paper in the journal PLOS Pathogens described how they synthetically engineered mosquitoes to stop the spread of dengue fever, a viral tropical disease that sickens as many as 100 million people each year. Now imagine genetically tweaking an invasive species of mosquito to save native Hawaiian birds from extinction, or transferring genes from one species of endangered chestnut tree to another to help the latter resist blight. Employing the same sort of genetic engineering used to make a plant-based burger bleed, scientists are beginning to explore the ways synthetic biology could help protect biodiversity and conserve species.
Regulation of GM Organisms for Invasive Species Control
6701H. J. Mitchell and D. Bartsch, Frontiers in Bioengineering and Biotechnology, 7:1-11. 2020-01-21 18:17:37.
Invasive species can cause significant harm to the environment, agriculture, and human health, but there are often very limited tools available to control their populations. Gene drives (GD) have been proposed as a new tool which could be used to control or eliminate such species. Here, GD describes a variety of molecular biology applications which all enable the introduction of genetic elements at a higher than expected frequency. These elements can change the genotypes in target populations rapidly with consequences either for (intrinsic) fitness or host-parasite interaction, or both. Beneficial applications are foreseen for human and animal health, agriculture, or nature conservation. This rapidly developing technology is likely to have major impacts in the fight against various diseases, pests, and invasive species. The majority of GD applications involve genetic engineering and novel traits. Therefore, applicants and GMO regulators need to interact to achieve the benefits in innovation while cautiously avoiding unacceptable risks. The release into the environment may include transboundary movement and replacement of target populations, with potential impact on human/animal health and the environment. This article summarizes knowledge-based discussions to identify information gaps and analyzes scenarios for responsible introduction of GD organisms into the environment. It aims to connect the latest scientific developments with regulatory approaches and decision-making.
Beyond Mendelian genetics: Anticipatory biomedical ethics and policy implications for the use of CRISPR together with gene drive in humans.
6227M. W. Nestor and R. L. Wilson, Journal of Bioethical Inquiry, 2020:1-12. 2020-01-03 21:43:18.
Clustered regularly interspaced short palindromic repeats (CRISPR) genome editing has already reinvented the direction of genetic and stem cell research. For more complex diseases it allows scientists to simultaneously create multiple genetic changes to a single cell. Technologies for correcting multiple mutations in an in vivo system are already in development. On the surface, the advent and use of gene editing technologies is a powerful tool to reduce human suffering by eradicating complex disease that has a genetic etiology. Gene drives are CRISPR mediated alterations to genes that allow them to be passed on to subsequent populations at rates that approach one hundred per cent transmission. Therefore, from an anticipatory biomedical ethics perspective, it is possible to conceive gene drive being used with CRISPR to permanently ameliorate aberrant genes from wild-type populations containing mutations. However, there are also a number of possible side effects that could develop as the result of combining gene editing and gene drive technologies in an effort to eradicate complex diseases. In this paper, we critically analyse the hypothesis that the combination of CRISPR and gene drive will have a deleterious effect on human populations from an ethical perspective by developing an anticipatory ethical analysis of the implications for the use of CRISPR together with gene drive in humans.
Development of genetic control strategies for insect pests using CRISPR/Cas9 Développement de méthodes de lutte génétique contre de l’insecte nuisible basé sur le system CRISPR/Cas9
18505E. Green, Université de Strasbourg, 2019-12-17 14:20:21.
nsect pest control remains an important economic, environmental, and public health challenge. CRISPR/Cas9 gene drive (GD) is a novel genetic control strategy. GDs are genetic systems that can rapidly invade a population. This manuscript presents my efforts to develop gene drives in two important pest species, Anopheles gambiae, a major vector of malaria, and Drosophila suzukii, a global crop pest. The goals of this project were to develop a suppression gene drive in D. suzukii, to reduce population size, and a modification drive in An. gambiae, to reduce malaria transmission. While I was unable to produce a functional gene drive in D. suzukii, the efforts and protocols presented here can serve as a baseline for future work in this economically important crop pest. In An. gambiae, I successfully characterized two transgenic lines, one of which significantly blocks malaria transmission to a rodent model. Finally, I present my efforts to engineer a new modification gene drive strategy, indirect gene drive.
Effects of a male meiotic driver on male and female transcriptomes in the house mouse
6639A. Lindholm, A. Sutter, S. Kunzel, D. Tautz and H. Rehrauer, Proceedings of the Royal Society B-Biological Sciences, 286:1-8. 2019-11-13 20:18:05.
Not all genetic loci follow Mendel's rules, and the evolutionary consequences of this are not yet fully known. Genomic conflict involving multiple loci is a likely outcome, as restoration of Mendelian inheritance patterns will be selected for, and sexual conflict may also arise when sexes are differentially affected. Here, we investigate effects of the t haplotype, an autosomal male meiotic driver in house mice, on genome-wide gene expression patterns in males and females. We analysed gonads, liver and brain in adult same-sex sibling pairs differing in genotype, allowing us to identify t-associated differences in gene regulation. In testes, only 40% of differentially expressed genes mapped to the approximately 708 annotated genes comprising the t haplotype. Thus, much of the activity of the t haplotype occurs in trans, and as upregulation. Sperm maturation functions were enriched among both cis and trans acting t haplotype genes. Within the t haplotype, we observed more downregulation and differential exon usage. In ovaries, liver and brain, the majority of expression differences mapped to the t haplotype, and were largely independent of the differences seen in the testis. Overall, we found widespread transcriptional effects of this male meiotic driver in the house mouse genome.
What is genome editing?
14784NHGRI, NHGRI, 2019-08-15 17:41:15.
Genome editing is a method that lets scientists change the DNA of many organisms, including plants, bacteria, and animals. Editing DNA can lead to changes in physical traits, like eye color, and disease risk. Scientists use different technologies to do this.
Improving plant-resistance to insect-pests and pathogens: The new opportunities through targeted genome editing
6176D. S. Bisht, V. Bhatia and R. Bhattacharya, Seminars in Cell & Developmental Biology, 96:65-76. 2019-05-08 18:53:44.
The advantages of high input agriculture are fading away due to degenerating soil health and adverse effects of climate change. Safeguarding crop yields in the changing environment and dynamics of pest and pathogens, has posed new challenges to global agriculture. Thus, integration of new technologies in crop improvement has been imperative for achieving the breeding objectives in faster ways. Recently, enormous potential of genome editing through engineered nucleases has been demonstrated in plants. Continuous refinements of the genome editing tools have increased depth and breadth of their applications. So far, genome editing has been demonstrated in more than fifty plant species. These include model species like Arabidopsis, as well as important crops like rice, wheat, maize etc. Particularly, CRISPR/Cas9 based two component genome editing system has been facile with wider applicability. Potential of genome editing has unfurled enormous possibilities for engineering diverse agronomic traits including durable resistance against insect-pests and pathogens. Novel propositions of developing insect and pathogen resistant crops by genome editing include altering the effector-target interaction, knocking out of host-susceptibility genes, engineering synthetic immune receptor eliciting broad spectrum resistance, uncoupling of antagonistic action of defense hormones etc. Alternatively, modification of insect genomes has been used either to create gene drive or to counteract resistance to various insecticides. The distinct advantage of genome editing system is that it can knock out specific target region in the genome without leaving the unwanted vector backbone. In this article, we have reviewed the novel opportunities offered by the genome editing technologies for developing insect and pathogen resistant crop-types, their future prospects and anticipated challenges.
A potential new tool for the toolbox: assessing gene drives for eradicating invasive rodent populations
11550K. J. Campbell, J. R. Saah, P. R. Brown, J. Godwin, F. Gould, G. R. Howald, A. Piaggio, P. Thomas, D. M. Tompkins, D. Threadgill, J. Delborne, D. Kanavy, T. Kuiken, H. Packard, M. Serr and A. Shiels, Island invasives: scaling up to meet the challenge, 2019-03-05 14:59:34.
Invasive rodents have significant negative impacts on island biodiversity. All but the smallest of rodent eradications currently rely on island-wide rodenticide applications. Although signifi cant advances have been made in mitigating unintended impacts, rodent eradication on inhabited islands remains extremely challenging. Current tools restrict eradication eff orts to fewer than 15% of islands with critically endangered or endangered species threatened by invasive rodents. The Genetic Biocontrol of Invasive Rodents partnership is an interdisciplinary collaboration to develop and evaluate gene drive technology for eradicating invasive rodent populations on islands. Technological approaches currently being investigated include the production of multiple strains of Mus musculus with a modifi ed form of the native t-complex, or a CRISPR gene drive, carrying genes or mechanisms that determine sex. These systems have the potential to skew the sex ratio of off spring to approach 100% single-sex, which could result in population collapse. One goal proposed is to test the ability of constructs to spread and increase in frequency in M. musculus populations in biosecure, captive settings and undertake modelling to inform development and potential deployment of these systems. Structured ecologically-based risk assessments are proposed, along with social and cultural engagement to assess the acceptability of releasing a gene drive system. Work will be guided by an external ethics advisory board. Partners are from three countries with significant regulatory capacity (USA, Australia, New Zealand). Thus, we will seek data sharing agreements so that results from experiments may be used within all three countries and treat regulatory requirements as a minimum. Species-specific, scalable, and socially acceptable new eradication tools could produce substantial biodiversity benefits not possible with current technologies. Gene drive innovation may provide such a tool for invasive species management and be potentially transformative and worthy of exploring in an inclusive, responsible, and ethical manner.
CRISPR-Cas9. The greatest advancement in genetic edition techniques requires an ethical reflection
3913Gomez-Tatay, LA, J., Cuadernos De Bioetica, 30:171-185. 2019-01-11 00:00:00.
The adaptation of the CRISPR system as a genetic editing tool has led to a revolution in many fields of application, as this technique is considerably faster, easier to perform and more efficient than predecessor techniques. However, some of these applications raise objective ethical issues that must be addressed. In this paper we discuss, based on the most recent data, the different issues related to CRISPR applications on the germ line, its introduction in clinical trials, the genetic edition of animals and plants for human consumption and the novel gene drive.
CRISPR Explained
14780Mayo Clinic, 2018-07-24 17:25:24.
A short video that simply explains what CRISPR is and how it is used for gene editing. Simple language and highly accessible.
Gene Editing: Last Week Tonight with John Oliver (HBO)
6882J. Oliver, HBO, 2018-07-01 20:40:49.
Scientists are developing new ways to alter the genetic code of living organisms. John Oliver explores the risks, rewards, and wolf-related hazards of gene editing.
What is CRISPR?
14778A. Vidyasagar, LiveScience, 2018-04-21 17:17:15.
CRISPR technology is a simple yet powerful tool for editing genomes. It allows researchers to easily alter DNA sequences and modify gene function. Its many potential applications include correcting genetic defects, treating and preventing the spread of diseases and improving crops. However, its promise also raises ethical concerns.
Economic issues to consider for gene drives
3997Mitchell, PDB, Z.; McRoberts, N., Journal of Responsible Innovation, 5:S180-S202. 2018-01-15 00:00:00.
We examine four economic issues regarding gene drive applications made possible by gene editing technologies. First, whether gene drives are self-sustaining or self-limiting will largely determine which types of organizations have incentives to develop and deploy gene drives and greatly influence their governance and regulation. Social factors will also play key roles, particularly public perceptions, with these perceptions co-determined with regulation and governance. Second, gene drive applications will generate unintended negative social impacts that will partially offset benefits. Third, economic surplus, the traditional measure of economic benefits, incompletely captures the welfare impacts of gene drive applications. Fourth, gene drives imply dynamic nonlinearities that make identifying economic equilibria and general policy recommendations challenging. The potentially substantial benefits, coupled with the technical, social, and economic uncertainties surrounding gene drives, suggest that a responsible course of action is to move forward while maintaining regulatory flexibility and conducting research to resolve key uncertainties.
The use of gene editing to create gene drives for pest control in New Zealand
16070Royal Society Te Apārangi Gene Editing Panel, Royal Society of New Zealand, 2017-06-06 13:54:28.
to explore the implications of gene editing technology for New Zealand, the Royal Society Te Apārangi has convened a multidisciplinary panel of some of New Zealand’s leading experts to consider the social, cultural, legal and economic implications of revolutionary gene-editing technologies for New Zealand to: • Raise awareness of the scientific possibilities and associated public issues of new gene editing technologies to inform debate • Provide information and guidance for policy makers to address current and new issues needing to be clarified or resolved • Show where gene-editing applications are covered by established policies and regulations and where changes are needed • Provide a New Zealand perspective to the global discussion on this technology and identify where global consensus is important T
Genome editing: scientific opportunities, public interests and policy options in the European Union
16075EASAC, European Academies Science Advisory Council, 2017-03-01 14:41:21.
In many of the areas in which EASAC, the European Academies’ Science Advisory Council, works, where a large and solid body of knowledge is needed to inform the action of our societies, it is important to recognise that there is an intimate mix of science and values involved in discussion. Such discussions are most fruitful when both knowledge and values are well identified. This report presents a broad synthesis of genome editing, one of the newer aspects of the biosciences. It is our hope that presenting clearly the science involved – the duty of academies – will serve the ongoing discussions within society that the report recommends be vigorously pursued.
The End of the GMO? Genome Editing, Gene Drives and New Frontiers of Plant Technology
15368K. L. Hefferon and R. J. Herring, Review of Agrarian Studies, 7. 2017-01-01 21:40:33.
mprovements to agriculture will constitute one of the world’s greatest challenges in the coming century. Political and social controversies, as well as complications of plant breeding, intellectual property, and regulation, have compromised the promised impact of genetically engineered – typically transgenic – crops designated as “GMOs.” Genome editing is a new suite of molecular tools for assisting biologists identify genes that control agronomic traits such as drought tolerance and pest resistance, as well as to elucidate how expression of these genes is intertwined within the functional framework of the cell. This technology has recently gained momentum for its ability to accelerate the crop breeding process in an unprecedented fashion and expand the range of crop varieties with improved precision and lower costs. This review explains the basic concepts and provides examples of how genome editing could help address the United Nation’s Sustainable Development Goals with respect to food, agriculture, and medicine. It concludes with a discussion of the potential social impact of genome editing and gene drive. These effects are contingent on the resolution of novel ethical and regulatory challenges that add new layers of complexity to societal questions of appropriate technology, in agriculture and beyond. We expect these questions to replace the irresolvable GMO debate.
Regulatory experience and challenges for the release of GM insects
4135Beech, C, Journal Fur Verbraucherschutz Und Lebensmittelsicherheit-Journal of Consumer Protection and Food Safety, 9:S71-S76. 2014-01-13 00:00:00.
Genetically modified (GM) insects are a potentially valuable new tool for the biological control of insect pests of humans, animals and plants. Considerable progress has been made recently in transfer of GM insects from the laboratory to release and evaluation in the environment. As with other new genetic technologies, regulatory agencies have often found it challenging to determine the regulatory regime under which they should be evaluated, and have either adapted existing regulatory frameworks or adopted new ones. No country has legislation specifically for GM insects. However, irrespective of the regulatory regime under which they are evaluated, the purpose of their regulation remains the same; to protect human health and the environment. Consequently there are evaluation themes common to their regulatory scrutiny, which are elucidated here. There have also been some challenges and issues encountered during the risk evaluation for field release of GM insects, and this paper will highlight some of these to assist others when considering policy, regulation and assessment of GM insects. Useful regulatory and policy precedents also exist from the regulation of biological control agents and the global protection of plants from pests under the International Standards for Phytosanitary Measures (ISPM) framework. Where countries do not have existing regulations, these evaluation instruments could have the potential to be adapted to form a suitable framework for the assessment of risk for GM insects. Finally, some considerations for future policy and regulation in this area are discussed.
Malaria Control with Genetically Manipulated Insect Vectors
16035L. Alphey, C. B. Beard, P. Billingsley, M. Coetzee, A. Crisanti, C. Curtis, P. Eggleston, C. Godfray, J. Hemingway, M. Jacobs-Lorena, A. A. James, F. C. Kafatos, L. G. Mukwaya, M. Paton, J. R. Powell, W. Schneider, T. W. Scott, B. Sina, R. Sinden, S. Sink, Science, 298:119. 2002-10-04 19:49:32.
At a recent workshop, experts discussed the benefits, risks, and research priorities associated with using genetically manipulated insects in the control of vector-borne diseases.
Mariner transposition and transformation of the yellow fever mosquito, Aedes aegypti
6256C. J. Coates, N. Jasinskiene, L. Miyashiro and A. A. James, Proceedings of the National Academy of Sciences of the United States of America, 95:3748-3751. 1998-03-07 19:31:51.
The mariner transposable element is capable of interplasmid transposition in the embryonic soma of the yellow fever mosquito, Aedes aegypti. To determine if this demonstrated mobility could be utilized to genetically transform the mosquito, a modified mariner element marked with a wild type allele of the Drosophila melanogaster cinnabar gene was microinjected into embryos of a kynurenine hydroxylase-deficient, white-eyed recipient strain. Three of 69 fertile male founders resulting from the microinjected embryos produced families with colored-eyed progeny individuals, a transformation rate of 4%. The transgene-mediated complementation of eve color was observed to segregate in a Mendelian manner, although one insertion segregates with the recessive allele (female-determining) of the sex-determining locus, and a separate insertion is homozygous lethal. Molecular analysis of selected transformed families demonstrated that a single complete copy of the construct had integrated independently in each case acid that it had done so in a transposase-mediated manner. The availability of a mariner transformation system greatly enhances our ability to study and manipulate this important vector species.
Stable transformation of the yellow fever mosquito, Aedes aegypti, with the Hermes element from the housefly
6254N. Jasinskiene, C. J. Coates, M. Q. Benedict, A. J. Cornel, C. S. Rafferty, A. A. James and F. H. Collins, Proceedings of the National Academy of Sciences of the United States of America, 95:3743-3747. 1998-03-07 19:28:29.
The mosquito Aedes aegypti is the world's most important vector of yellow fever and dengue viruses, Work is currently in progress to control the transmission of these viruses by genetically altering the capacity of wild Ae, aegypti populations to support virus replication. The germ-line transformation system reported here constitutes a major advance toward the implementation of this control strategy, A modified Hermes transposon carrying a 4.7-kb fragment of genomic DNA that includes a wild-type allele of the Drosophila melanogaster cinnabar (cn) gene was used to transform a white-eyed recipient strain of Ae, aegypti. Microinfection of preblastoderm mosquito embryos with this construct resulted in 50% of the emergent G(0) adults showing some color in their eyes, Three transformed families were recovered, each resulting from an independent insertion event of the cn(+)-carrying transposon, The cn(+) gene functioned as a semidominant transgene and segregated in Mendelian ratios, Hermes shows great promise as a vector for efficient, heritable, and stable transformation of this important mosquito vector species.
Gene transfer into the Medfly, Ceratitis capitata, using a Drosophila hydei transposable element.
6269T. G. Loukeris, I. Livadaras, B. Arca, S. Zabalou and C. Savakis, Science, 270:2002-2005. 1995-12-22 16:35:47.
Exogenous functional DNA was introduced into the germline chromosomes of the Mediterranean fruit fly (medfly) Ceratitis capitata with a germline transformation system based on the transposable element Minos from Drosophila hydei. Transformants were identified as phenotypic revertants of a white-eyed mutation carried by the recipient strain. Clusters of transformants were detected among the progeny of 390 individuals screened for germline transformation. Five independent and phenotypically active integration events were identified, in each of which a single copy of the transposon was inserted into a different site of the medfly genome. Molecular analysis indicates that they represent transposase-mediated insertions of the transposon into medfly chromosomes.
Genetic-transformation of Drosophila with transposable element vectors
6252G. M. Rubin and A. C. Spradling, Science, 218:348-353. 1982-10-22 19:25:36.
Exogenous DNA sequences were introduced into the Drosophila germ line. A rosy transposon (ry1), constructed by inserting a chromosomal DNA fragment containing the wild-type rosy gene into a P transposable element, transformed germ line cells in 20 to 50 percent of the injected rosy mutant embryos. Transformants contained one or two copies of chromosomally integrated, intact ry1 that were stably inherited in subsequent generations. These transformed flies had wild-type eye color indicating that the visible genetic defect in the host strain could be fully and permanently corrected by the transferred gene. To demonstrate the generality of this approach, a DNA segment that does not confer a recognizable phenotype on recipients was also transferred into germ line chromosomes.
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