Keywords: Self limiting
Highlight: Self-limiting gene drive suppresses malaria mosquitoes
35263Gorm Palmgren, CRISPR Medicine News, 2025-11-02 17:22:29.
Malaria claimed over 600,000 lives in 2022, with Anopheles gambiae serving as one of the most efficient vectors in sub-Saharan Africa, where approximately 96% of malaria deaths occur. The emergence of insecticide resistance threatens progress in disease control, prompting the development of genetic strategies to address it. CRISPR-homing gene drives have emerged as the most studied self-sustaining approaches, whilst various self-limiting methods that require repeated releases continue to be explored. The research team developed a system, termed Male-Drive Female-Sterile (MDFS), that exploits CRISPR-Cas9 to simultaneously perform two distinct functions (see Figure 1). The genetic construct contains an eCFP fluorescent marker, a Cas9 endonuclease under the control of the germline vasa2 promoter, and a guide RNA targeting the female-specific exon 5 of the doublesex gene. The construct was integrated into the doublesex locus at the intron 4–exon 5 boundary using recombinase-mediated cassette exchange.
A comparative assessment of self-limiting genetic control strategies for population suppression
34572Yue Han, Jackson Champer, Molecular Biology and Evolution, 2025-03-12 16:21:17.
Genetic control strategies are promising solutions for control of pest populations and invasive species. Methods utilizing repeated releases of males such as Sterile Insect Technique (SIT), Release of Insects carrying a Dominant Lethal (RIDL), self-limiting gene drives, and gene disruptors are highly controllable methods, ensuring biosafety. Although models of these strategies have been built, detailed comparisons are lacking, particularly for some of the newer strategies. Here, we conducted a thorough comparative assessment of self-limiting genetic control strategies by individual-based simulation models. Specifically, we find that repeated releases greatly enhance suppression power of weak and self-limiting gene drives, enabling population elimination with even low efficiency and high fitness costs. Moreover, dominant female sterility further strengthens self-limiting systems that can either use gene drive or disruptors that target genes without a mechanism to bias their own inheritance. Some of these strategies are highly persistent, resulting in relatively low release ratios even when released males suffer high fitness costs. To quantitively evaluate different strategies independent from ecological impact, we proposed constant-population genetic load, which achieves over 95% accuracy in predicting simulation outcomes for most strategies, though it is not as precise in a few frequency-dependent systems. Our results suggest that many new self-limiting strategies are safe, flexible, and more cost-effective than traditional SIT and RIDL, and thus have great potential for population suppression of insects and other pests.
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.
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?
CRISPR’d Mosquitoes With All-Male Offspring Could Help Eradicate Malaria
26610V. B. Ramirez, Singuarity Hub, 2023-07-13 13:17:26.
Though at least one vaccine for malaria is in use, it remains one of the deadliest diseases in the world. Almost half of the world’s population lives in areas where malaria transmission occurs, and an estimated 619,000 people died of the disease in 2021. Worse yet, the vast majority of cases leading to death are in young children. Researchers from the University of California in San Diego may have found a way to reduce this burden of disease. They used the gene editing tool CRISPR to alter a gene that controls sexual development in mosquitoes. Male mosquitoes don’t bite humans; it’s the females that spread malaria and other diseases. The UCSD team’s method uses gene editing to kill all female mosquito offspring within a given population of the insects. The mosquito species in question is Anopheles gambiae, commonly called the African malaria mosquito and described as “the most efficient vector of human malaria.” They’re anthropophilic, meaning they like human blood more than animal blood, and they thrive in hot climates with a lot of moisture. Why such an insect exists in the first place is hard to comprehend, is it not?
CRISPR/Cas9-based split homing gene drive targeting doublesex for population suppression of the global fruit pest Drosophila suzukii
25710A. K. Yadav, C. Butler, A. Yamamoto, A. A. Patil, A. L. Lloyd and M. J. Scott, Proc Natl Acad Sci U S A, 120:e2301525120. 2023-06-13 10:38:33.
Genetic-based methods offer environmentally friendly species-specific approaches for control of insect pests. One method, CRISPR homing gene drive that target genes essential for development, could provide very efficient and cost-effective control. While significant progress has been made in developing homing gene drives for mosquito disease vectors, little progress has been made with agricultural insect pests. Here, we report the development and evaluation of split homing drives that target the doublesex (dsx) gene in Drosophila suzukii, an invasive pest of soft-skinned fruits. The drive component, consisting of dsx single guide RNA and DsRed genes, was introduced into the female-specific exon of dsx, which is essential for function in females but not males. However, in most strains, hemizygous females were sterile and produced the male dsx transcript. With a modified homing drive that included an optimal splice acceptor site, hemizygous females from each of the four independent lines were fertile. High transmission rates of the DsRed gene (94 to 99%) were observed with a line that expressed Cas9 with two nuclear localization sequences from the D. suzukii nanos promoter. Mutant alleles of dsx with small in-frame deletions near the Cas9 cut site were not functional and thus would not provide resistance to drive. Finally, mathematical modeling showed that the strains could be used for suppression of lab cage populations of D. suzukii with repeated releases at relatively low release ratios (1:4). Our results indicate that the split CRISPR homing gene drive strains could potentially provide an effective means for control of D. suzukii populations.
To fight berry-busting fruit flies, researchers focus on sterilizing the bugs
25719M. Walling, KTAL News.com, 2023-06-13 09:42:56.
Paul Nelson is used to doing battle with an invasive fruit fly called the spotted wing drosophila, a pest that one year ruined more than half the berries on the Minnesota farm he and his team run. In recent years, they’ve cut their losses closer to 5%, but it’s been labor-intensive and expensive. “It’s a pest that if you’re not willing to stick the time into it, it’s going to take over your farm,” said Nelson, the head grower at Untiedt’s, a vegetable and fruit operation about an hour west of Minneapolis. Nelson and other growers may someday get a new tool as a result of research at North Carolina State University into the insects, which ruin the berries by laying their eggs in them and have been estimated to cost growers hundreds of millions of dollars annually. The researchers, using a concept called “gene drive,” manipulated the insects’ DNA so that the female offspring would be sterile, and the method they used to achieve it significantly reduced the chance that a population could rebound.
CRISPR/Cas9-based gene drive could suppress agricultural pests
25706North Carolina State University, Phys Org, 2023-06-12 10:22:37.
Researchers have developed a "homing gene drive system" based on CRISPR/Cas9 that could be used to suppress populations of Drosophila suzukii vinegar flies—so-called "spotted-wing Drosophila" that devastate soft-skinned fruit in North America, Europe and parts of South America—according to new research from North Carolina State University. The NC State researchers developed dual CRISPR gene drive systems that targeted a specific D. suzukii gene called doublesex, which is important for sexual development in the flies. CRISPR stands for "clustered regularly interspaced short palindromic repeats" and Cas9 is an enzyme that performs like molecular scissors to cut DNA. CRISPR systems are derived from bacterial immune systems that recognize and destroy viruses and other invaders, and are being developed as solutions to problems in human, plant and animal health, among other uses. Targeting the doublesex gene resulted in female sterility in numerous experiments as females were unable to lay eggs, says Max Scott, an NC State entomologist who is the corresponding author of a paper in Proceedings of the National Academy of Sciences that describes the research. "This is the first so-called homing gene drive in an agricultural pest that potentially could be used for suppression," Scott said. Gene drives can preferentially select, change or delete particular traits or characteristics and "drive" those edits through future generations, resulting in a sometimes far greater than 50% chance of passing those changes to progeny.
Modelling the effect of migration on the localisation and spread of a gene drive
24955C. Benjamin James and F.-L. Alexandre Jules Hen, bioRxiv, 2023.04.02.535303. 2023-04-04 14:22:19.
Gene drives have the potential to address pressing ecological issues. Through the super-Mendelian inheritance of a gene drive, a trait can be spread through a population even in spite of a fitness cost. This ability to spread is both its greatest quality and detractor. We may not want a gene drive to spread universally. If a gene drive were designed to cause the collapse of a pest population, it may inadvertently cause the collapse of the entire species. Migration is the mechanism through which a gene drive can spread to distant populations. Understanding its effect on the progression of a gene drive is crucial to our ability to control a gene drive. While migration can spread the gene drive to other populations, equally it can bring in other alleles to the population that may disrupt the progression of the gene drive. Through our deterministic migration gene drive model we can assess the conditions in which a gene drive is likely to spread to unintended populations, and if a gene drive is likely to be displaced by incoming alleles.Competing Interest StatementThe authors have declared no competing interest.
Researchers Create New System for Safer Gene-Drive Testing and Development
24471M. Aguilera, UC San Diego Today, 2023-01-12 08:46:16.
In the journal Nature Communications, University of California San Diego researchers led by former Postdoctoral Scholar Gerard Terradas together with Postdoctoral Scholar Zhiqian Li and Professor Ethan Bier, in close collaboration with UC Berkeley graduate student Jared Bennett and Associate Professor John Marshall, describe the development of a new system for testing and developing gene drives in the laboratory and safely converting them into tools for potential real-world applications. “These studies both empower new engineering of gene-drive systems while providing important information regarding how to assess and analyze key interactions between their most important moving parts,” said Bier, a faculty member in the School of Biological Sciences, Department of Cell and Developmental Biology. CRISPR-based gene drives feature a protein called a Cas9 endonuclease and a guide RNA molecule that join forces to direct DNA cuts to specific sites in the genome where new genetic elements can be inserted. As the DNA repairs these cuts, the new genetic elements are copied from one chromosome to another, resulting in offspring that exceed the standard 50-50 percent inheritance, instead favoring the newly inserted genetic elements.
Oxitec’s mosquitoes are getting “friendly” with California
24109L. Patrick, The Sun Gazette, 2022-12-01 09:34:07.
Biotech company Oxitec is buzzing around Visalia, with the hopes of releasing their genetically engineered mosquitoes in Tulare County. Oxitec has one more hurdle to jump over in order to release their “friendly” Aedes aegypti mosquitoes in Tulare County, and that’s to gain the approval of the California Department of Pesticide Regulation (DPR). Though their attempts to release their GE mosquitoes in California have been met with both supportive and hesitant reactions from different state agencies and environmental groups, Oxitec’s Dr. Kevin Gorman said the technology has been researched and reviewed with “much scrutiny,” despite claims that the mosquitoes are ineffective or hazardous. “We have a biological approach to managing pest insects, and the biological approach is a mating-based technology. It’s very targeted, it only affects the species that [they’re] mating with,” Gorman said. “Not only is it environmentally safe, it’s effective.” The male GE mosquitoes from Oxitec have been engineered with a self-limiting gene, and this gene infects wild female mosquitoes to prevent them from reproducing female offspring. This leaves only male mosquitoes in the gene pool, according to Gorman. Female mosquitoes are targeted since they are the only ones that bite, and therefore capable of transmitting diseases. The engineered males will only mate with Aedes aegypti females, and do not leave an environmental footprint, according to Gorman. The release of these mosquitoes is supposed to reduce the natural population of the invasive mosquito, which are known to carry diseases such as dengue, chikungunya, Zika, yellow fever and others.
Turns Out Fighting Mosquitoes With Mosquitoes Actually Works
24018E. Mullin, Wired, 2022-11-21 08:56:57.
In the Brazilian city of Indaiatuba, an effort is underway to eliminate these pests before they have a chance to spread illness. The weapon: more Aedes aegypti mosquitoes—but ones genetically engineered to kill their own kind. Made by British biotechnology firm Oxitec, the mosquitoes seem to be working. The modified mosquitoes carry a synthetic self-limiting gene that prevents female offspring from surviving. This is important, because only the females bite and transmit disease. In a new study, scientists at the company showed that their engineered insects were able to slash the local population of Aedes aegypti by up to 96 percent over 11 months in the neighborhoods where they were released. “This is an area with high levels of Aedes aegypti, and they periodically have outbreaks of dengue,” says Nathan Rose, head of malaria programs at Oxitec. In fact, this summer the Brazilian Ministry of Health reported that dengue fever was continuing to spread in all five regions of the country. Between January 1 and May 31, Brazil had more than 1.1 million cases—an increase of 198 percent compared to the same period in 2021. In those five months, the disease, which causes high fever, rash, and muscle and joint pain, killed 504 people. For the study, which was conducted in 2018 and 2019, the company chose four densely populated neighborhoods with high levels of Aedes aegypti. In two, scientists released a “dose” of 100 male mosquitoes per resident per week. In the others, they cranked that up to 500.
Daisy-chain gene drives: The role of low cut-rate, resistance mutations, and maternal deposition
23623S. A. N. Verkuijl, M. A. E. Anderson, L. Alphey and M. B. Bonsall, PLOS Genetics, 18:e1010370. 2022-09-19 14:37:34.
Author summary Reducing the harm of pest species by the introgression of traits into a wild population is often limited by the difficulties of mass rearing and release of modified individuals. Gene drives present an opportunity to substantially reduce the release frequencies required to spread a particular modification. However, uniform modification of a target species is, with a few specific exceptions, not necessary or desirable. Self-limiting gene drives, such as daisy-chain gene drives, have been widely discussed as a potential solution, allowing the invasiveness of a drive release to be tuned to the target population. Here, we investigate through computational modelling how daisy-chain gene drives perform when subjected to commonly observed inefficiencies associated with CRISPR-Cas9-based inheritance biasing. Compared to a self-perpetuating drive, daisy-chain gene drives are sensitive to factors that cause their separate elements to segregate prematurely. In particular, a reduction in the DNA cut-rate and an increase in the formation of resistance alleles. We find that the effect of inefficiencies in the drive mechanism is generally more pronounced when the drive is at low frequencies. With low rates of migration, this substantially reduces daisy-chain gene drives spread into a neighbouring non-target population.
A confinable female-lethal population suppression system in the malaria vector, Anopheles gambiae
23500A. L. Smidler, J. J. Pai, R. A. Apte, H. M. Sánchez C, R. M. Corder, E. J. Gutiérrez, N. Thakre, I. Antoshechkin, J. M. Marshall and O. S. Akbari, bioRxiv, 2022.08.30.505861. 2022-08-30 19:10:47.
Malaria is among the world’s deadliest diseases, predominantly affecting sub-Saharan Africa, and killing over half a million people annually. Controlling the principal vector, the mosquito Anopheles gambiae, as well as other anophelines, is among the most effective methods to control disease spread. Here we develop an innovative genetic population suppression system termed Ifegenia (Inherited Female Elimination by Genetically Encoded Nucleases to Interrupt Alleles) in this deadly vector. In this bicomponent CRISPR-based approach, we disrupt a female-essential gene, femaleless (fle), demonstrating complete genetic sexing via heritable daughter gynecide. Moreover, we show that Ifegenia males remain reproductively viable, and can load both fle mutations and CRISPR machinery to induce fle mutations in subsequent generations, resulting in sustained population suppression. Through modeling, we demonstrate that iterative releases of non-biting Ifegenia males can act as an effective, confinable, controllable, and safe population suppression and elimination system.
A multiplexed, confinable CRISPR/Cas9 gene drive propagates in caged Aedes aegypti populations
23429M. A. E. Anderson, E. Gonzalez, M. P. Edgington, J. X. D. Ang, D.-K. Purusothaman, L. Shackleford, K. Nevard, S. A. N. Verkuijl, T. Harvey-Samuel, P. T. Leftwich, K. Esvelt and L. Alphey, bioRxiv, 2022.08.12.503466. 2022-08-12 07:19:58.
Here, we test the regulatory sequences from the Ae. aegypti benign gonial cell neoplasm (bgcn) homolog to express Cas9 in the germline to find an expression timing more conducive to homing. We also created a separate multiplexing (targeting multiple different sites within the target gene) sgRNA-expressing homing cassette inserted into the Ae. aegypti kynurenine 3-monooxygenase (kmo) gene to limit the consequences of resistance alleles. This creates a ‘split’ gene drive such that one part does not drive, allowing control over geographic spread and temporal persistence. When combined, these two elements provide highly effective germline cutting at the kmo locus and act as a gene drive. Our target genetic element was driven through a cage trial population such that carrier frequency of the element increased 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.Significance statement Mosquito-borne diseases affect millions of people worldwide, with the yellow fever mosquito (Aedes aegypti) being the principal vector of many viral diseases. Effective measures for controlling this mosquito are sorely needed. Gene drive systems have arisen as a potential tool for mosquito control due to their ability of biasing inheritance of a trait into a target population. Here, we assess a split gene drive, based on CRISPR/Cas9 endonuclease technology driving a target element into the mosquito population. Evaluated over successive generations in a replicated cage trial, the drive successfully biased its inheritance, increasing in frequency from 50% to up to 89%. Our results are encouraging for the potential use of this type of contained gene drive system for mosquito control in endemic areas.Competing Interest StatementThe authors have declared no competing interest.
Propagation of seminal toxins through binary expression gene drives could suppress populations
21691J. Hurtado, S. Revale and L. M. Matzkin, Scientific Reports, 12:6332. 2022-04-15 08:22:57.
Gene drives can be highly effective in controlling a target population by disrupting a female fertility gene. To spread across a population, these drives require that disrupted alleles be largely recessive so as not to impose too high of a fitness penalty. We argue that this restriction may be relaxed by using a double gene drive design to spread a split binary expression system. One drive carries a dominant lethal/toxic effector alone and the other a transactivator factor, without which the effector will not act. Only after the drives reach sufficiently high frequencies would individuals have the chance to inherit both system components and the effector be expressed. We explore through mathematical modeling the potential of this design to spread dominant lethal/toxic alleles and suppress populations. We show that this system could be implemented to spread engineered seminal proteins designed to kill females, making it highly effective against polyandrous populations.
Genetic conversion of a split-drive into a full-drive element
19540G. Terradas, J. B. Bennett, Z. Li, J. M. Marshall and E. Bier, bioRxiv, 2021.12.05.471291. 2021-12-06 20:21:27.
Gene-drive systems offer an important new avenue for spreading beneficial traits into wild populations. Their core components, Cas9 and guide RNA (gRNA), can either be linked within a single cassette (full gene drive, fGD) or provided in two separate elements (split gene drive, sGD) wherein the gRNA-bearing element drives in the presence of an independent static source of Cas9. We previously designed a system engineered to turn split into full gene drives. Here, we provide experimental proof-of-principle for such a convertible system inserted at the spo11 locus, which is recoded to restore gene function. In multigenerational cage studies, the reconstituted spo11 fGD cassette initially drives with slower kinetics than the unlinked sGD element (using the same Mendelian vasa-Cas9 source), but eventually reaches a similar level of final introgression. Different kinetic behaviors may result from transient fitness costs associated with individuals co-inheriting Cas9 and gRNA transgenes during the drive process.
Propagation of seminal toxins through binary expression gene drives can suppress polyandrous populations
19953J. Hurtado, S. Revale and L. M. Matzkin, bioRxiv, 2021.11.23.469777. 2021-11-24 09:48:59.
Gene drives can be highly effective in controlling a target population by disrupting a female fertility gene. To spread across a population, these drives require that disrupted alleles be largely recessive so as not to impose too high of a fitness penalty. We argue that this restriction may be relaxed by using a double gene drive design to spread a split binary expression system. One drive carries a dominant lethal/toxic effector alone and the other a transactivator factor, without which the effector will not act. Only after the drives reach sufficiently high frequencies would individuals have the chance to inherit both system components and the effector be expressed. We explore through mathematical modeling the potential of this design to spread dominant lethal/toxic alleles and suppress populations. We show that this system could be implemented to spread engineered seminal proteins designed to kill females, making it highly effective against polyandrous populations.Competing Interest StatementThe authors have declared no competing interest.
Genetic control of invasive sea lamprey in the Great Lakes
19270D. Ferreira-Martins, J. Champer, D. W. McCauley, Z. Zhang and M. F. Docker, Journal of Great Lakes Research, 2021-11-08 16:16:20.
The invasive sea lamprey was a significant factor in the collapse of fish stocks in the Great Lakes, and it continues to threaten the multi-billion-dollar fishing industry. Thus, substantial resources are invested annually on sea lamprey control. Current control strategies have reduced sea lamprey populations by up to 90%, but they are expensive and have some limitations, e.g., lamprey-specific biocides applied to larval habitat impact native lampreys, and physical barriers that block adult lamprey access to spawning habitat impede migration of other fishes. Therefore, genetic control options which offer a theoretically powerful and effective pest control tool are being explored, although they have uncertain sociopolitical support, especially given the need to protect sea lamprey in their native range in Atlantic drainages. Here, we present an overview of genetic approaches with potential for application to sea lamprey control in the Great Lakes. We classify these approaches into two major categories: self-limiting (heritable sex ratio ratchet, Trojan gene, split gene drive) and self-sustaining (gene drive-based sex ratio distortion, homing suppression gene drive, toxin-antidote gene drives, and modification-type gene drives to aid suppression). We describe the technical aspects, challenges, and potential application of each method, focusing on gene drives, a fast-evolving research area that was only a distant option for sea lamprey control in previous reviews. We conclude that, given the risk of undesired spread of deleterious alleles from the Great Lakes, self-limiting genetic control options and confined gene drives will likely be preferred over unconfined gene drive options for sea lamprey control.
CRISPR/Cas9-based functional characterization of the pigmentation gene ebony in Plutella xylostella
18155X. Xu, T. Harvey-Samuel, J. Yang, M. You and L. Alphey, Insect Molecular Biology, 2021-08-20 17:59:44.
Abstract Body pigmentation is an important character of insects in adapting to biotic and abiotic environmental challenges. Additionally, based on the relative ease of screening, several genes involved in insect melanisation have been used in classic genetic studies or as visual markers in constructing transgenic insects. Here, a homolog of the Bombyx mori melanisation-inhibiting gene ebony, associated with the conversion of dopamine to N-?-alanyl dopamine, was identified in a global pest, Plutella xylostella. The CRISPR/Cas9 system was applied to generate multiple Pxebony knockout alleles which were crossed to produce a Pxebony knockout strain, showing darker pigmentation in larvae, pupae and adults, compared with wildtype. Interestingly, we observed that Pxebony heterozygotes displayed an intermediate darkened phenotype, indicating partial dominance between the knockout and wildtype alleles. The fitness costs of Pxebony-deficiency were also assessed in the mutant strain, indicating that embryo hatchability and larval survival were significantly reduced, while the eclosion rate was not obviously affected. Our work provides a potential target for exploring CRISPR-based genetics-control systems in this economically important pest lepidopteran.
Gene drive that results in addiction to a temperature sensitive version of an essential gene triggers population collapse in Drosophila
17609G. Oberhofer, B. Hay and T. Ivy, bioRxiv, 2021.07.03.451005. 2021-07-04 14:38:01.
One strategy for population suppression seeks to use gene drive to spread genes that confer conditional lethality or sterility, providing a way of combining population modification with suppression. Stimuli of potential interest could be introduced by humans, such as an otherwise benign virus or chemical, or occur naturally on a seasonal basis, such as a change in temperature. Cleave and Rescue (ClvR) selfish genetic elements use Cas9 and gRNAs to disrupt endogenous versions of an essential gene, while also including a Rescue version of the essential gene resistant to disruption. ClvR spreads by creating loss-of-function alleles of the essential gene that select against those lacking it, resulting in populations in which the Rescue provides the only source of essential gene function. In consequence, if function of the Rescue, a kind of Trojan horse now omnipresent in a population, is condition-dependent, so too will be the survival of that population. To test this idea we created a ClvR in Drosophila in which Rescue activity of an essential gene, dribble, requires splicing of a temperature-sensitive intein (TS-ClvRdbe). This element spreads to transgene fixation at 23° C, but when populations now dependent on TS-ClvRdbe are shifted to 29° C death and sterility result in a rapid population crash. These results show that conditional population elimination can be achieved. A similar logic, in which Rescue activity is conditional, could also be used in HEG-based drive, and to bring about suppression and/or killing of specific individuals in response to other stimuli.Competing Interest StatementThe authors have filed patent applications on ClvR and related 336 technologies (U.S. Application No. 15/970,728 and No. 16/673,823 ; provisional patent No. 337 CIT-8511-P )
Village hears from experts as genetic-mosquito release experiment nears.
16678J. McCarthy, KEYSWEEKLY, 2021-03-26 14:56:47.
On March 18, Islamorada Village Council heard from several independent scientists who discussed information and issues behind the genetically modified mosquitoes for population and disease suppression. The scientists collectively said they’re neither for nor against the release. A representative from the Florida Keys Mosquito Control District and one from Oxitec responded following the presentation. Fred Gould, professor of North Carolina State’s Department of Entomology and Plant Pathology, briefly explained the strain of mosquitoes (OX5034) set for release. He said he was involved with another strain of genetically modified mosquitoes in development in 2010 when a field case study was conducted in Mexico. “In the laboratory, it turned out the male mosquitoes flew fine and mated well. But in the real environment, they weren’t as strong as the wild type mosquitoes and they basically had 3% of the matings. Instead of having half the matings, they had very few,” he said. Gould went on to say that this is also shown in work by Oxitec in Brazil, where it turns out that the genetic mosquitoes “are not very fit.” “It would take 30 of them, at least, to be equal to an individual wild type in terms of how many matings you have,” he said. “When you’re thinking about that, you have to recognize you have to release a lot of mosquitoes in order to have any activity. I just want to bring that home to you that it goes up and down as to what that percent fitness is, and we don’t know what that’ll look like in Florida. “Will it work? I want to say it might work just fine,” he continued. “There’s a chance that they’ll be doing these releases and it won’t be a simple thing.”
Mosquito anxiety prompts query from congressman
16592T. Java, Keynews.com, 2021-03-10 20:09:26.
Anxiety among some residents over the pending release of hundreds of millions of genetically modified mosquitoes next month in undisclosed locations throughout the Florida Keys has prompted Congressman Carlos Gimenez to seek answers from the U.S. Environmental Protection Agency. The Florida Keys Mosquito Control District and Oxitec, a British-based biotech company, plan to release genetically modified Aedes aegypti mosquitoes in selected neighborhoods between mile markers 10 and 93 as a way to control the wild population of the disease-carrying pest. This is the first experiment of its kind in the U.S.
Gene Drives Built to Follow More Stringent Rules of the Road
16590Anonymous, Genetic Engineering & Biotechnology News, 2021-03-08 19:57:32.
Gene drives, or systems that accelerate the spread of desirable genetic traits into a population, may be built to achieve specific levels of spread when released into the wild. By exerting control over the degree of spread, those who unleash gene drives may realize the benefits promised by gene drives—the suppression of disease-carrying or crop-destroying insects—while minimizing the risks that unintended genetic changes could occur that would lead to undesirable ecological outcomes. A gene drive engineered to allow for a high degree of control was recently introduced by scientists based at the University of California, San Diego (UCSD). The new gene drive is a “split drive” system. Details appeared in an article titled, “Inherently confinable split-drive systems in Drosophila.” The article demonstrates that split-drive systems may allow various genetic parameters and strategies to be used to either limit or extend drive potential.
Gene-Editing Approach To Control the Invasive Gray Squirrel
16572M. Campbell, Technology Networks, 2021-03-08 14:33:09.
Biodiversity refers to the extent of the variety of life that is found on planet Earth – and it is currently under threat. Changes in biodiversity have been flagged as "surpassing safe limits" for several years, and world leaders and scientists across the globe are consequently exploring different ways to address the crisis. Invasive species, defined by National Geographic as "an organism that is not indigenous, or native, to a particular area", threaten planet Earth's biodiversity to an even greater extent than climate change. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment Report found that the number of invasive species per country have risen by ~70% since 1970 across 21 countries that were included in the report. An example of an invasive species is the gray squirrel Sciurus carolinensis found in the UK, which outcompetes the native red squirrel for resources and habitats and carries diseases that are not pathogenic to themselves but can kill red squirrels.
New gene-drive technologies can help control crop pests
16569Anonymous, AZO Life Sciences, 2021-03-08 14:21:28.
The supposed gene drives, which exploit CRISPR technology to affect genetic inheritance, show the potential to quickly spread particular genetic traits across the populations of a specified species. For instance, gene-drive technologies used on insects are being developed to stop the spread of devastating diseases, like dengue and malaria, by inhibiting mosquito hosts from becoming infected. Gene-drives are being designed in agricultural fields to help regulate or remove economically damaging crop pests. But together with the potential to modify populations, there have been concerns about the long-term impacts of these transformative novel technologies in the wild. Both scientists and ethicists have queried about how the so-called gene drives, once turned loose in a regional population, can be controlled if required. Scientists from the University of California San Diego (UC San Diego), Tata Institute for Genetics and Society (TIGS) at UC San Diego, and their collaborators at UC Berkeley have now designed a new technique that gives more control over the release of gene drives. Information about the new “split drive” was published in the Nature Communications and eLife journals on March 5th, 2021.
New ‘Split-drive’ System Puts Scientists in the (Gene) Driver Seat
16555M. Aguilera, UC San Diego News Center, 2021-03-05 19:42:37.
Gene-drive technologies applied in insects, for example, are being designed to halt the spread of devastating diseases such as malaria and dengue by preventing mosquito hosts from becoming infected. In agricultural fields, gene-drives are being developed to help control or eliminate economically damaging crop pests. But along with the capacity to alter populations, concerns have been raised regarding the long-term effects of these transformative new technologies in the wild. Researchers and ethicists have voiced questions about how gene drives, once turned loose in a regional population, could be held in check if necessary. Now, researchers at the University of California San Diego, Tata Institute for Genetics and Society (TIGS) at UC San Diego and their colleagues at UC Berkeley have developed a new method that provides more control over gene drive releases. Details of the new “split drive” are published March 5 in the journals Nature Communications and eLife.
Ecology: Gene drives may help control invasive grey squirrel in the UK
16557A. Korn, EurekaAlert, 2021-03-04 19:50:50.
Gene drives introduce genes into a population that have been changed to induce infertility in females, allowing for the control of population size. However, they face technical challenges, such as controlling the spread of altered genes as gene drive individuals mate with wild individuals, and the development of genetic resistance, which may render the gene drive ineffective. To address these challenges, Nicky Faber and colleagues used computer modelling to investigate the effectiveness of a combination of three gene drive technologies using the grey squirrel as a case study.
Genetically modified squirrels could curb growing population of greys
16542S. Knapton, Telegraph, 2021-03-04 16:06:59.
Mutant grey squirrels, genetically modified to spread infertility genes, could be released into the wild to tackle the burgeoning population,
Expert reaction to a paper suggesting that gene drives could be used to help control grey squirrel numbers in the UK
16540Anonymous, Science Media Centre, 2021-03-04 15:59:10.
This study assesses the prospects for using a gene drive to control invasive grey squirrels in the UK. This is a modelling study exploring the potential for such an approach – no such gene drives currently exist and developing them for grey squirrels would be quite a long-term project. Invasive species are a major problem for biodiversity and conservation; in many cases there are no adequate methods for control. Genetic methods may provide new options, potentially both more effective and with fewer off-target effects. Most work on gene drives has focused on mosquitoes; this study is unusual in focusing on a vertebrate (grey squirrel), though there has also been interest in targeting invasive populations of mice and rats on islands.
CRISPR gene drives may come to a squirrel near you.
16536Anonymous, NewsBeezer, 2021-03-04 15:48:43.
Today’s gene drive technologies could be blended to provide control of the invasive gray squirrel population in the UK – with minimal risk to other populations, according to a new modeling published in the journal Scientific reports. Gene driving introduces altered genes into a population that can cause infertility in women. This allows scientists to control the size of the population. However, this tactic faces technical difficulties such as controlling the spread of altered genes while certain animals that are part of the gene drive population mate with uncontrolled populations ̵
Tensions rise as GM mosquito release nears in Florida Keys
16520T. O'Hara, Keynews.com, 2021-03-03 20:29:44.
Tensions seem to be rising as a planned release of genetically modified mosquitoes nears. The British-based biotech company Oxitec plans to release genetically modified Aedes aegypti mosquitoes in the Florida Keys sometime after April, but has yet to disclose exact locations in the Keys or a date.
Florida Keys moves forward with genetically modified mosquitoes
16524H. Vela, local10.com, 2021-03-03 18:08:13.
The feared GMO mosquitoes are not going away. Opponents of the technology fear the date of the release in the Florida Keys is getting closer, and they are not ready for the possible repercussions of the experiment. The fight over whether or not to release genetically modified mosquitoes in Monroe County has been going on for almost a decade. Barry Wray said the mosquito control team’s contractor wants to deliver the first batch in April. Wray, the executive director of the Florida Keys Environmental Coalition, said he doesn’t believe there is enough evidence to prove that the technology is safe. He said there is a need for independent scientific investigation. “You don’t really know what the long-term outcomes could be or how to quantify those risks, and if you can’t do that scientifically, then you don’t know how to responsibly mitigate it or detect if something is going awry,” Wray said.
When and where will millions of mosquitoes be released? Here are details for Florida Keys
16485D. Goodhue, Miami Herald, 2021-02-25 21:09:17.
The Florida Keys Mosquito Control District announced this week a wide and vague planned range of deployment for the lab-designed mosquitoes — neighborhoods from mile marker 10 to 93. The trial is being conducted by British biotech company Oxitec. It’s a method approved by the U.S. Environmental Protection Agency, the state of Florida, and the mosquito control district’s five-member board, to try to eradicate or significantly reduce the local population of Aedes aegypti mosquitoes.
Mosquito trial will begin in April, but Keys locations won’t be disclosed
16483S. Matthis, KEYSWEEKLY, 2021-02-23 20:54:42.
FKMCD spokesman Chad Huff wrote in an email, “The physical location of each box is still being finalized. Since most will be situated on private property at owner request, FKMCD-Oxitec will NOT be providing specific addresses due to privacy concerns and protection of project integrity.” Phil Goodman, chairman of the FKMCD said the decision to keep addresses confidential was an operations decision, not a decision by the elected board. “Right now, we don’t have any specific sites that are 100 percent selected,” said Andrea Leal, executive director of the FKMCD. “We are just narrowing down areas with potential.”
Split versions of Cleave and Rescue selfish genetic elements for measured self limiting gene drive
16426G. Oberhofer, T. Ivy and B. A. Hay, PLoS genetics, 17:e1009385. 2021-02-18 20:00:28.
Self-sustaining Cleave and Rescue (ClvR) elements include a DNA sequence-modifying enzyme such as Cas9/gRNAs that disrupts endogenous versions of an essential gene, a tightly linked recoded version of the essential gene resistant to cleavage (the Rescue), and a Cargo. ClvR spreads by creating loss-of-function (LOF) conditions in which those without ClvR die because they lack functional copies of the essential gene. We use modeling to show that when the Rescue-Cargo and one or both components required for LOF allele creation (Cas9 and gRNA) reside at different locations (split ClvR), drive of Rescue-Cargo is self-limiting due to a progressive decrease in Cas9 frequency, and thus opportunities for creation of LOF alleles, as spread occurs. Importantly, drive strength and duration can be extended in a measured manner-which is still self-limiting-by moving the two components close enough to each other that they experience some degree of linkage. With linkage, Cas9 transiently experiences drive by hitchhiking with Rescue-Cargo until linkage disequilibrium between the two disappears, a function of recombination frequency and number of generations, creating a novel point of control. We implement split ClvR in Drosophila, with key elements on different chromosomes. Cargo/Rescue/gRNAs spreads to high frequency in a Cas9-dependent manner, while the frequency of Cas9 decreases.
Oxitec gears up for test releases
16386T. O'Hara, Keynews.com, 2021-02-10 15:10:19.
The United Kingdom-based biotech company Oxitec will soon announce the test locations and timetable for releasing its genetically modified mosquitoes in the Florida Keys.
Self-Deleting Genes Project To Tackle Mosquito-Borne Diseases
15923D. Ozdemir, INTERESTING ENGINEERING, 2021-01-08 18:58:57.
Did you know that mosquitoes kill at least 725,000 persons every year? They truly are one of the world's deadliest animals which is the reason why scientists from all around are trying to find new ways of dealing with them. Controlling mosquito populations and preventing them from transmitting disease at times through genetic engineering is one way of doing that. Now, a new Texas A&M AgriLife Research project has plans of enabling "test runs" of the proposed changes in mosquitoes that are automatically deleted from their genetic code. Researchers have used genetic engineering in the past to modify mosquitoes in a way that they pass on infertility, don't grow wings, can't spread malaria, or have impaired smell. However, as New Atlas reports, this sort of modification can have harmful consequences that may be impossible to reverse when released into the wild.
Edit, undo: Temporary gene editing could help solve the mosquito problem
15900L. Dormehl, digitaltrends, 2020-12-31 14:22:29.
But if SyFy original movies have taught us anything, it’s that genetically tweaking organisms and then releasing them can… well, not go quite according to plan.With that in mind, a new Texas A&M AgriLife Research project seeks to test out genetic modifications of mosquitos that would delete themselves from the genetic code after a certain period. This means that “test runs” of genetic changes could be made, knowing that everything will reset to normal after a designated period like one year (which equates to around 20 generations of mosquito).
Self-deleting genes promise risk-free genetic engineering of mosquitoes
15852D. Quick, New Atlas, 2020-12-29 18:53:49.
A new project by Texas A&M AgriLife Research is looking to enable "test runs" of genetic changes to mosquitoes that are automatically deleted. Various angles of attack using genetic engineering to combat mosquitoes have been pursued in recent years, including modifying them so they pass on infertility, don't grow wings, can't spread malaria or have impaired smell. But making genetic modifications to an organism and then releasing them into the wild runs the risk of unintended and harmful consequences that may be difficult to reverse. That's where the new Texas A&M AgriLife Research project comes in. It is looking to enable "test runs" of genetic modifications that would then automatically be deleted from the mosquitoes' genetic code after a period of time.
Self-deleting genes to be tested as part of mosquito population control concept
15926B. Hays, UPI, 2020-12-28 18:59:14.
Scientists at Texas A&M have developed a new technique for altering the genes of mosquitoes -- the new technology will cause genetic changes to self-delete from the mosquitoes' genome. Thanks to the breakthrough, described Monday in the Philosophical Transactions of the Royal Society B, researchers can now test-run experimental gene edits without permanently altering a mosquito's genome."People are wary of transgenes spreading in the environment in an uncontrolled manner. We feel that ours is a strategy to potentially prevent that from happening," Zach Adelman, professor of entomology at the Texas A&M College of Agriculture, said in a news release. "The idea is, can we program a transgene to remove itself? Then, the gene won't persist in the environment."
$3.9M project on self-deleting genes takes aim at mosquito-borne diseases
15847O. Kuchment, AGRILIFE Today, 2020-12-28 18:52:03.
To control mosquito populations and prevent them from transmitting diseases such as malaria, many researchers are pursuing strategies in mosquito genetic engineering. A new Texas A&M AgriLife Research project aims to enable temporary “test runs” of proposed genetic changes in mosquitoes, after which the changes remove themselves from the mosquitoes’ genetic code. The project’s first results were published on Dec. 28 in Philosophical Transactions of the Royal Society B, titled “Making gene drive biodegradable.”
Self-deleting genes tested as part of the concept of mosquito population control
15844charlottelarson, NEWYORK NEWS TIMES, 2020-12-28 18:49:28.
Most genetic engineering strategies designed to control mosquito populations, and their ability to spread diseases such as malaria, require gene editing to be combined with gene drives. Gene drives allow altered DNA to spread rapidly throughout the population.
Making gene drive biodegradable
15687J. Zapletal, N. Najmitabrizi, M. Erraguntla, M. A. Lawley, K. M. Myles and Z. N. Adelman, Philosophical Transactions of the Royal Society B: Biological Sciences, 376:20190804. 2020-12-28 15:02:10.
Here, we consider the inclusion of self-elimination mechanisms into the design of homing-based gene drive transgenes. This approach not only caused the excision of the gene drive transgene, but also generates a transgene-free allele resistant to further action by the gene drive. Strikingly, our models suggest that this mechanism, acting at a modest rate (10%) as part of a single-component system, would be sufficient to cause the rapid reversion of even the most robust homing-based gene drive transgenes, without the need for further remediation.
A CRISPR endonuclease gene drive reveals two distinct mechanisms of inheritance bias
15480S. A. N. Verkuijl, E. González, J. X. D. Ang, M. Li, N. P. Kandul, M. Anderson, O. S. Akbari, M. Bonsall and L. Alphey, bioRxiv, 2020.12.15.421271. 2020-12-16 14:45:08.
In this study, we report the functioning of sds3, bgcn, and nup50 expressed Cas9 in an Aedes aegypti homing split drive system targeting the white gene. We report their inheritance biasing capability, propensity for maternal deposition, and zygotic/somatic expression. Additionally, by making use of the tight linkage of white to the sex-determining locus, we were able to elucidate mechanisms of inheritance bias. We find inheritance bias through homing in double heterozygous males, but find that a previous report of the same drive occurred through meiotic drive. We propose that other previously reported 'homing'design gene drives may in fact bias their inheritance through other mechanisms with important implications for gene drive design.Competing Interest StatementThe authors have declared no competing interest.
Split drive killer-rescue provides a novel threshold-dependent gene drive
15254M. P. Edgington, T. Harvey-Samuel and L. Alphey, Scientific Reports, 10. 2020-11-25 18:32:01.
Population genetics mathematical models are developed here to demonstrate the threshold-dependent nature of the proposed system and its robustness to imperfect homing, incomplete penetrance of toxins and transgene fitness costs, each of which are of practical significance given that real-world components inevitably have such imperfections. We show that although end-joining repair mechanisms may cause the system to break down, under certain conditions, it should persist over time scales relevant for genetic control programs. The potential of such a system to provide localised population suppression via sex ratio distortion or female-specific lethality is also explored. Additionally, we investigate the effect on introduction thresholds of adding an extra CRISPR base element, showing that this may either increase or decrease dependent on parameter context
Fighting Mosquito With GMO Mosquito: The Battle Brewing in the Florida Keys
15005S. MacLaughlin, NBC 6 South Florida, 2020-11-06 15:32:04.
Scientists are a few months into an experiment to stop the invasive Aedes aegypti mosquito. Their weapon of choice? A genetically modified mosquito. But some environment advocates question the strategy. This year, the Florida Keys had an outbreak of Dengue fever, which was the first time that had happened in 10 years. It gives new urgency to the controversial effort to get rid of the Aedes aegypti, which has become harder to fight.
Florida will release 750 million genetically modified mosquitoes
14998S. McGlaun, Slash Gear, 2020-11-05 15:14:43.
Local officials in Florida have announced that they have approved 750 million genetically modified mosquitoes to be released into the environment to reduce local populations of the bloodsucking creatures. The goal of releasing genetically modified mosquitoes is to help reduce the number of mosquitoes carrying diseases like dengue or the Zika virus. Approval to release the bugs came after environmental groups warned of unintended consequences.
Gene Drives across engineered fitness valleys: Modeling a design to prevent drive spillover.
14880F. J. H. de Haas and S. Otto, bioRxiv, 2020.10.29.360404. 2020-10-29 15:44:22.
We model a proposed drive system that transitions in time from a low threshold drive system (homing-based gene drive) to a high threshold drive system (underdominance) using daisy chain technology. This combination leads to a spatially restricted drive strategy while maintaining an attainable release threshold.
Florida to Release 750 Million GMO Mosquitoes in 2021
14703Seeker, Seeker, 2020-10-13 18:11:21.
The U.S. EPA gave the green light to release millions of genetically modified mosquitoes in the Florida Keys in 2021 — here’s what we know.
You should be excited that scientists are releasing 750 million genetically modified mosquitoes this year
14568L. Westreich, Massive Science, 2020-09-27 19:27:28.
GM mosquitoes are successful in reducing mosquito populations, and reducing disease spread
The Con Job at Mosquito Control Board
14571E. Russo and B. Wray, keysnews.com, 2020-09-26 19:32:07.
Shouldn’t there be a consensus among scholars, scientists, experts and the public that this new technology is safe?
GMOs make war on mosquitoes
14323Staff, Kenosha News, 2020-09-05 15:13:38.
Given that recent record, we were a bit surprised to read that there was a ruckus over genetically modified mosquitoes going on in the Florida Keys.
Why Genetically Modified Mosquitoes Won’t Come to Texas Anytime Soon
14317C. Adams, RA News, 2020-09-04 15:03:04.
Talks about releasing genetically modified mosquitoes in Houston began in 2018 between Harris County and Oxitec, a United Kingdom-based company that produces sustainable technologies or transgenic methodologies to stem the impact of disease-spreading insects. Talk also began about a similar action in Monroe County, Fla.
Inherently confinable split-drive systems in Drosophila
14294G. Terradas, A. B. Buchman, J. B. Bennett, I. Shriner, J. M. Marshall, O. S. Akbari and E. Bier, bioRxiv, 2020.09.03.282079. 2020-09-03 14:16:46.
Here, we test split gene-drive (sGD) systems in Drosophila melanogaster that were inserted into essential genes required for viability (rab5, rab11, prosalpha2) or fertility (spo11). I
An accident waiting to happen: Tech company to release 750 MILLION GMO mosquitoes in Florida to fight dengue fever
14232Z. Sky, NEWSTARGET, 2020-08-30 20:31:13.
Oxitec plans to release 750 million OX5034s into the Florida Keys, something that sounds like the beginning of a doomed science-fiction movie. But the most shocking thing here is the fact that Oxitec received the EPA’s approval in May.
Genetically-modified mosquito plan offers hope for Keys, world
14256P. Goodman, keynews.com, 2020-08-29 14:25:12.
The Florida Keys Mosquito Control District Board of Commissioners voted 4-to-1 to approve a trial using Oxitec’s second-generation genetically modified mosquitoes. I
The good mosquito versus the bad
14240D. Datta, Business Standard, 2020-08-29 14:01:00.
Starting 2021, around 750 million genetically modified (GM) Aedes Aegypti mosquitoes will be released in batches into the Florida Keys.
Florida Will Release 750 Genetically Modified Mosquitoes to Stop Disease Spread
14177A. Fahmy, verywell health, 2020-08-28 14:36:32.
The hope is to prevent the spread of Dengue fever, a painful virus acquired only by mosquito bite which made a reappearance in the Florida Keys in 2009.
Novel combination of CRISPR-based gene drives eliminates resistance and localises spread
14172N. R. Faber, G. R. McFarlane, R. C. Gaynor, I. Pocrnic, C. B. A. Whitelaw and G. Gorjanc, bioRxiv, 2020-08-27 14:22:46.
We present HD-ClvR, a novel combination of CRISPR-based gene drives that eliminates resistance and localises spread. As a case study, we model HD-ClvR in the grey squirrel (Sciurus carolinensis), which is an invasive pest in the UK and responsible for both biodiversity and economic losses.
Deep dive: Florida’s GM mosquito experiment aims to rewrite rules of vector-borne diseases
14084S. Kannan, India Today, 2020-08-26 14:33:36.
A pathbreaking bioengineering experiment on mosquito populations that could have massive implications for tropical malaria-affected countries like India has got underway in Florida, US.
Fighting mosquito-borne diseases… with mosquitoes
14156N. Gubert and A. Baubeau, Phys Org, 2020-08-26 13:13:41.
For decades, researchers have scratched their heads over how to combat deadly mosquito-borne diseases such as dengue fever.
Bug board OKs release of genetically modified mosquitoes
14151T. O'Hara, keynews.com, 2020-08-26 13:08:07.
After nearly 10 years of debate, the Florida Keys Mosquito Control District board has approved an agreement with biotech company Oxitec to conduct a test release of genetically modified mosquitoes in Monroe County as part of a mosquito limiting or eradication plan.
Genetically modified mosquitoes to be released in the Florida Keys to combat dengue, zika, and yellow fever.
14148Yucatan Times, Yucatan Times, 2020-08-26 13:04:27.
The Florida Keys will be the scene of the first test in the United States with genetically modified Aedes aegypti mosquitoes, an alternative to insecticides and larvicides to end the transmission of diseases such as dengue, zika and yellow fever that has always been surrounded by controversy.
Transgenic moths released to end one of the worst pests on the planet
14099B. Mandalia, Pledge Times, 2020-08-25 14:49:50.
Today the results of the first open field experiment with another of the creations of this biotechnology company are published. It is a variant of the moth Plutella xylostella which is one of the worst agricultural pests in the world.
750 million genetically modified mosquitoes soon released in the wild!
14093explica, explica, 2020-08-25 14:42:52.
Rather frightening mosquitoes will be released on an archipelago in Florida. The goal? Reduce the population of their more dangerous congeners who can transmit certain diseases.
US to Use Genetically Modified Mosquitoes to Fight Dengue Fever
14090H. Badr, Asharq Al-Awsat, 2020-08-25 14:39:32.
After a decade of discussions, officials in Florida have voted to allow the first test in the United States of free-flying, genetically modified mosquitoes that kill any female offspring, as a way to fight the pests and the diseases they spread.
Florida Keys to Use Genetically Modified Mosquitoes to Fight Disease
14087B. Lynn, Voice of America, 2020-08-25 14:33:57.
Officials in the Florida Keys plan to release genetically modified mosquitoes next year in an effort to fight insect-borne diseases.
Florida Approves Controversial Plan to Release 750 Million Genetically Modified Mosquitoes
14096D. Rakshit, Swaddle, 2020-08-24 14:46:17.
Authorities in Florida have approved a pilot project that will release 750 million genetically modified mosquitoes locally, in a bid to reduce the populations of mosquitoes that cause that cause dengue, Zika, chikungunya, and yellow fever
Mutant bugs released to fight disease
14081The Day, The Day, 2020-08-24 14:20:37.
Authorities have approved the scheme in Florida but environmental groups are furious, calling it a “Jurassic Park experiment” that will unleash a “mutant bug” into the ecosystem.
More than 750 million GMO mosquitoes to be released over Florida Keys – what could go wrong?
14145E. Huff, Natural News, 2020-08-24 12:59:20.
The Florida Keys Mosquito Control District (FKMCD) has given Oxitec, a corporation we have reported on in the past, permission to unleash some 750 million GMO mosquitos in Monroe County, Florida, over the next two years.
Florida to release genetically modified mosquitoes to prevent diseases like Zika
14009The West News, The West News, 2020-08-23 17:50:16.
Local authorities on Tuesday gave final approval to release 750 million genetically modified mosquitoes in the Florida Keys over a two-year period, starting in 2021.
Genetically modified mosquitoes have been OK’d for a first U.S. test flight
14003S. Milius, ScienceNews, 2020-08-22 17:44:31.
After a decade of fits and starts, officials in the Florida Keys have voted to allow the first test in the United States of free-flying, genetically modified mosquitoes as a way to fight the pests and the diseases they spread.
Florida Will Release Genetically Modified Mosquitoes to Fight Disease in the Keys
14000S. Harrell, Spectrum News, 2020-08-21 17:40:14.
Following lengthy federal and state procedures, the Florida Keys Mosquito Control District this week approved a plan to release more than 750 million genetically modified mosquitoes in the Keys region to combat an invasive, disease-carrying species of the insect.
Florida is releasing 750 million genetically modified mosquitoes into the world. Here’s why
13992H. Schriber, Deseret News, 2020-08-21 17:35:50.
Florida officials plan to release 750 million genetically modified mosquitoes into the Florida Keys over the next two years as a way to prevent diseases like the Zika virus. The project will begin in 2021. The Environment Protection Agency approved the idea in May. The project will test if one of these mosquitoes can work better than spraying insecticides to stop these insects from spreading potentially fatal viruses, according to CNN.
Genetically Modified Mosquitoes To Be Released In Florida Keys
13989A. Snow, The Daily Wire, 2020-08-21 17:33:00.
CNN reported that the genetically modified bugs, called OX5034, have been “altered to produce female offspring that die in the larval stage, well before hatching and growing large enough to bite and spread disease.” Since it’s the female of the species that bite, they are the ones that carry diseases. Males, the outlet reported, eat nectar.
Release 750 Million Genetically Modified Mosquitoes Into the Wild, They Said
13986C. Delbert, Popular Mechanics, 2020-08-21 17:31:14.
Corporate scientists have received final approval from the Environmental Protection Agency (EPA) to release hundreds of millions of genetically altered mosquitoes into the Florida Keys. The goal? To begin reining in the mosquito population, which is only expected to increase as climate change continues to warm and flood the low-lying, tropical Keys. But some environmental groups object strongly to the move.
Florida releasing genetically modified mosquitoes to prevent diseases like Zika
13984N. Lanese, LiveScience, 2020-08-21 17:29:18.
Hundreds of millions of genetically modified mosquitoes will soon be released in the Florida Keys island chain to wipe out local populations of disease-carrying mosquitoes, according to news reports.
750 Million GM Mosquitoes Will Be Released in the Florida Keys
13982L. Winter, The Scientist, 2020-08-21 17:27:30.
With the aim of reducing rates of the mosquito-borne illnesses yellow fever and dengue, a pilot program will release 750 million genetically modified mosquitoes into the Florida Keys in 2021, thanks to approval by the barrier islands’ Mosquito Control District Board of Commissioners at a meeting on Tuesday (August 18)
Hundreds Of Millions Of Genetically Modified Mosquitoes Approved For Release In US
13996J. Vibes, Anonymous News, 2020-08-20 17:37:24.
A Biotech company called Oxitec has received permission from the government to release hundreds of millions of genetically modified male mosquitoes in the Florida Keys.
Why Hundreds of Millions of Genetically Engineered Mosquitoes Will Soon Be Released in Florida
13979K. Gander, Newsweek, 2020-08-20 17:22:07.
Hundreds of millions of genetically engineered mosquitoes will soon be released in Florida, in a first for the U.S. On Tuesday, the Florida Keys Mosquito Control District (FKMCD) approved plans to release the insects, who do not bite, as part of a pilot project launching next yea
Florida to release genetically modified mosquitoes, detractors blast ‘Jurassic Park’ experiment
13969D. Aaro, Fox News, 2020-08-20 15:49:28.
Local authorities on Tuesday gave final approval to release 750 million genetically modified mosquitoes in the Florida Keys over a two-year period, starting in 2021, with the hope of preventing diseases such as the Zika virus but has faced blowback and comparisons to a Steven Spielberg thriller.
750 million genetically modified mosquitoes to be released across Florida Keys
13966A. Zahid, Sky News, 2020-08-20 15:47:05.
Authorities have approved plans for genetically modified mosquitoes to be released across the Florida Keys from next year. British-based firm Oxitec has designed the project to test whether the altered mosquitoes are a viable alternative to pesticides to control and prevent the spread of diseases, including Zika and dengue.
750 million GM mosquitos set for release in Florida Keys.
13961Editorial Staff, E&T, 2020-08-20 15:43:13.
Local authorities have approved proposals to release hundreds of millions of genetically modified (GM) modified mosquitos in Florida, in an effort to control populations of diseases spread by the organism.
Florida Plans to Fix Its Mosquito Problem With 750 Million More Mosquitoes
13959D. Noor, Gizmodo, 2020-08-20 15:40:34.
Hundreds of millions of mosquitos will soon be released in Florida. On purpose. The mosquitoes are being released as a form of pest control, but they could wreak havoc on local ecosystems.
Florida mosquitoes: 750 million genetically modified insects to be released
13955BBC, BBC, 2020-08-20 15:37:01.
Local officials in Florida have approved the release of 750 million mosquitoes that have been genetically modified to reduce local populations. The aim is to reduce the number of mosquitoes that carry diseases like dengue or the Zika virus.
Florida OKs release of genetically modified mosquitoes in Keys to slow insect disease spread
13952S. Mann, Just the News, 2020-08-20 15:34:23.
Florida officials are authorizing a biotech company to release hundreds of millions of genetically-modified male mosquitoes into the Florida Keys to reduce future mosquito populations that spread diseases including yellow fever and malaria.
Florida Keys to release modified mosqutioes to fight illness
13949C. Anderson, Associated Press, 2020-08-20 15:30:15.
Sometime next year, genetically modified mosquitoes will be released in the Florida Keys in an effort to combat persistent insect-borne diseases such as Dengue fever and the Zika virus. The plan approved this week by the Florida Keys Mosquito Control District calls for a pilot project in 2021 involving the striped-legged Aedes aegypti mosquito, which is not native to Florida.
Florida to Release Millions of Genetically Modified Mosquitoes Against Local Residents’ Wishes
13946N. Rice, People, 2020-08-20 15:27:38.
A plan to release over 750 million genetically modified mosquitoes in the Florida Keys has received final approval. According to CNN, on Tuesday, local authorities approved a plan to release the genetically modified mosquitoes in the Sunshine State's string of islands, with the hope of preventing a string of diseases that the insects can carry.
Plan to Release 750M GMO Mosquitoes Gets Go Ahead
13944R. Quinn, newser, 2020-08-20 15:23:41.
The plan to release the genetically modified Aedes aegypti mosquitoes received final approval from local authorities Tuesday, causing an outcry from groups opposed to what they call a "Jurassic Park experiment," CNN reports.
‘A Jurassic Park Experiment’: Watchdog Groups Denounce Decision to Release Genetically Modified Mosquitoes in Florida
13975L. Newcomb, Common Dreams, 2020-08-19 15:54:09.
Food safety and environmental groups Wednesday condemned a decision by officials in Florida to approve the release of 750 million genetically modified mosquitoes, a pilot project aimed at reducing the spread of mosquito-borne diseases.
Florida Keys to release 750M genetically modified mosquitoes
13972D. Haynes, UPI, 2020-08-19 15:51:58.
Local authorities in the Florida Keys gave their approval Wednesday to a plan to release genetically modified mosquitoes to prevent the spread of dengue fever and other diseases. The Monroe County Mosquito Control District signed off on the project, which would release about 750 million mosquitoes engineered to produce dead offspring.
To combat disease-spreading mosquitoes in the Keys, leaders vote to unleash lab bugs
13964D. Goodhue, Miami Herald, 2020-08-19 15:44:52.
Florida Keys officials have voted to allow the experimental release of millions of genetically modified mosquitoes into a yet-to-be-decided area of the island chain.
2-Locus Cleave and Rescue; selfish elements harness a recombination rate-dependent generational clock for self limiting gene drive
13150G. Oberhofer, T. Ivy and B. A. Hay, bioRxiv, 2020-07-09 14:03:42.
Self-limiting gene drive allows control over the spread and fate of linked traits. Cleave and Rescue (ClvR) elements create self-sustaining drive and comprise a DNA sequence-modifying enzyme (Cas9-gRNAs, Cleaver) that disrupts an essential gene, and a tightly linked, uncleavable version of the essential gene (Rescue). ClvR spreads by creating conditions in which those without it die because they lack essential gene function. We show that when ClvR is implemented in a 2-locus format, with key elements – Rescue (and Cargo), and Cas9 and/or gRNAs – located at different genomic positions, spread of the Rescue is self-limiting. Drive strength and duration are determined by a recombination rate-dependent generational clock, providing an important point of control for different ecological and regulatory contexts. We implement 2-locus ClvR in Drosophila. Rescue spreads to high frequency in a Cas9-dependent manner, while the frequency of Cas9 decreases, demonstrating transient drive and loss of future drive potential.
Genetically engineered moths may save kale chips
7357C. Poku, BIOtechNOW, 2020-02-07 21:49:10.
Sea salt kale chips, bacon brussels sprouts, and buffalo cauliflower wings are under threat. Environmental activists will have you believe the biggest threat to our food system is pesticides. That’s not true, in fact, it’s insects—the very reason most pesticides are necessary. Insects are such a dangerous issue that Somalia recently declared a state of emergency as an “unprecedented” swarm of locusts is raising alarms about famine. Climate change has led to a rampant increase in bugs like locusts and moths, that threaten our food, and mosquitoes and ticks, that threaten people. A recent CNN article explains that diamondback moths are one of the most damaging insects because of their high reproduction rate and resistance to most insecticides.
Genetically engineered moths have been released into the wild to wipe out pests
7360K. Rogers, CNN, 2020-02-03 21:55:17.
Genetically modified diamondback moths designed to wipe out wild pest populations were released in fields for the first time in New York state. Diamondback moths are migratory pests found in the Americas, Europe, New Zealand and Southeast Asia, but especially in areas where crops can be grown yearround. In these parts -- where it's not too hot nor too cold -- are where diamondback moths cause the greatest problems, including billions of dollars in damages to cruciferous crops such as cabbage, broccoli, cauliflower and canola. They're one of the most damaging insects because of their high reproduction rate and resistance to most insecticides.
GMO diamondback moth shows promise as sustainable pest control tool in first ever open-field release
7262Cornell University, Genetic Literacy Project, 2020-01-29 16:35:41.
A newly published study reports a successful, first-ever open-field release of a self-limiting, genetically engineered diamondback moth, stating that it paves the way for an effective and sustainable approach to pest control. The diamondback moth, also known as Plutella xylostella, is highly damaging to brassica crops such as cabbage, broccoli, cauliflower and canola. This new strain of diamondback moth, developed by Oxitec Ltd, is modified to control pest diamondback moth in a targeted manner. The study showed the engineered strain had similar field behaviors to unmodified diamondback moths, with results offering promise for future protection of farmers’ brassica crops.
Male moths genetically modified to kill females released in the wild
7253M. Le Page, New Scientist, 2020-01-29 16:14:01.
Genetically modified male diamondback moths designed to wipe out pest populations have been released in New York state. The field trial shows that these GM moths, whose female offspring die soon after hatching, could help control this major crop pest. Oxitec, the British biotechnology company behind the trial, has already carried out field trials of this method for controlling mosquitoes that spread diseases such as dengue. However, the moth field trial is the first for a crop pest, the company says.
First Field Release of a Genetically Engineered, Self-Limiting Agricultural Pest Insect: Evaluating Its Potential for Future Crop Protection
7251A. M. Shelton, S. J. Long, A. S. Walker, M. Bolton, H. L. Collins, L. Revuelta, L. M. Johnson and N. I. Morrison, Frontiers in Bioengineering and Biotechnology, 7:1-15. 2020-01-29 16:10:21.
Alternative, biologically-based approaches for pest management are sorely needed and one approach is to use genetically engineered insects. Herein we describe a series of integrated field, laboratory and modeling studies with the diamondback moth, Plutella xylostella, a serious global pest of crucifers. A “self-limiting” strain of Plutella xylostella (OX4319L), genetically engineered to allow the production of male-only cohorts of moths for field releases, was developed as a novel approach to protect crucifer crops. Wild-type females that mate with these self-limiting males will not produce viable female progeny. Our previous greenhouse studies demonstrated that releases of OX4319L males lead to suppression of the target pest population and dilution of insecticide-resistance genes. We report results of the first open-field release of a non-irradiated, genetically engineered self-limiting strain of an agricultural pest insect. In a series of mark-release-recapture field studies with co-releases of adult OX4319L males and wild-type counterparts, the dispersal, persistence and field survival of each strain were measured in a 2.83 ha cabbage field. In most cases, no differences were detected in these parameters. Overall, 97.8% of the wild-type males and 95.4% of the OX4319L males recaptured dispersed <35 m from the release point. The predicted persistence did not differ between strains regardless of release rate. With 95% confidence, 75% of OX4319L males released at a rate of 1,500 could be expected to live between 3.5 and 5.4 days and 95% of these males could be expected to be detected within 25.8–34.9 m from the release point. Moth strain had no effect on field survival but release rate did. Collectively, these results suggest similar field behavior of OX4319L males compared to its wild-type counterpart. Laboratory studies revealed no differences in mating competitiveness or intrinsic growth rates between the strains and small differences in longevity. Using results from these studies, mathematical models were developed that indicate release of OX4319L males should offer efficacious pest management of P. xylostella. Further field studies are recommended to demonstrate the potential for this self-limiting P. xylostella to provide pest suppression and resistance management benefits, as was previously demonstrated in greenhouse studies.
‘We don’t want to be guinea pigs’: how one African community is fighting genetically modified mosquitoes
15233A. Pujol-Mazzini, The Telegraph, 2019-10-08 16:47:08.
Researchers from the Target Malaria consortium, a not-for-profit research group funded by the Bill & Melinda Gates Foundation and various research institutions, have developed a mosquito in their laboratory that can kill off its own species by spreading a faulty gene. If it works in the wild, the technology – called gene drive – could help eliminate malaria where decades of efforts involving bed nets, repellents and insecticides have failed.
Assessment of a split homing based gene drive for efficient knockout of multiple genes
5915Kandul, N. P., J. Liu, A. Buchman, V. M. Gantz, E. Bier and O. S. Akbari, bioRxiv, 2019:706929. 2019-07-18 16:34:25.
Homing based gene drives (HGD) possess the potential to spread linked cargo genes into natural populations and are poised to revolutionize population control of animals. Given that host-encoded genes have been identified that are important for pathogen transmission, targeting these genes using guide RNAs as cargo genes linked to drives may provide a robust method to prevent transmission. However, effectiveness of the inclusion of additional guide RNAs that target separate host encoded genes has not been thoroughly explored. To test this approach, here we generated a split-HGD in Drosophila melanogaster that encoded a drive linked effector consisting of a second gRNA engineered to target a separate host encoded gene, which we term a gRNA-mediated effector (GME). This design enabled us to assess homing and knockout efficiencies of two target genes simultaneously, and also explore the timing and tissue specificity of Cas9 expression on cleavage/homing rates. We demonstrate that inclusion of a GME can result in high efficiency of disruption of its target gene during super-Mendelian propagation of split-HGD. However, maternal deposition and embryonic expression of Cas9 resulted in the generation of drive resistant alleles which can accumulate and limit the spread of such a drive. Alternative design principles are discussed that could mitigate the accumulation of resistance alleles while incorporating a GME.
Split-gene drive system provides flexible application for safe laboratory investigation and potential field deployment
13625V. L. Del Amo, A. L. Bishop, H. M. Sánchez C, J. B. Bennett, X. Feng, J. M. Marshall, E. Bier and V. M. Gantz, bioRxiv, 684597. 2019-06-27 13:35:03.
CRISPR-based gene drives spread through populations bypassing the dictates of Mendelian genetics, offering a population-engineering tool for tackling vector-borne diseases, managing crop pests, and helping island conservation efforts; unfortunately, current technologies raise safety concerns for unintended gene propagation. Herein, we address this by splitting the two drive components, Cas9 and gRNAs, into separate alleles to form a novel trans-complementing split–gene-drive (tGD) and demonstrate its ability to promote super-Mendelian inheritance of the separate transgenes.
Daisyfield gene drive systems harness repeated genomic elements as a generational clock to limit spread
13623J. Min, C. Noble, D. Najjar and K. M. Esvelt, bioRxiv, 104877. 2017-02-06 13:30:21.
Here we describe a novel form of gene drive based on the introduction of multiple copies of an engineered ‘daisy’ sequence into repeated elements of the genome. Each introduced copy encodes guide RNAs that target one or more engineered loci carrying the CRISPR nuclease gene and the desired traits. When organisms encoding a drive system are released into the environment, each generation of mating with wild-type organisms will reduce the average number of the guide RNA elements per ‘daisyfield’ organism by half, serving as a generational clock
The promise and peril of CRISPR gene drives
4076Zentner, GEW, Michael J. C., Bioessays, 39:1-9. 2017-01-14 00:00:00.
Gene drives are selfish genetic elements that use a variety of mechanisms to ensure they are transmitted to subsequent generations at greater than expected frequencies. Synthetic gene drives based on the clustered regularly interspersed palindromic repeats (CRISPR) genome editing system have been proposed as a way to alter the genetic characteristics of natural populations of organisms relevant to the goals of public health, conservation, and agriculture. Here, we review the principles and potential applications of CRISPR drives, as well as means proposed to prevent their uncontrolled spread. We also focus on recent work suggesting that factors such as natural genetic variation and inbreeding may represent substantial impediments to the propagation of CRISPR drives.
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