Scholarly Literature
This is a database of scholarly literature that concentrates currently on natural and engineered selfish genetic elements (gene drives). The latest are shown here.
Disclaimer>
Wolbachia endosymbionts manipulate the self-renewal and differentiation of germline stem cells to reinforce fertility of their fruit fly host
28215S. L. Russell, J. R. Castillo and W. T. Sullivan, PLOS Biology, 21:e3002335. 2023-10-24 14:41:16.
The alphaproteobacterium Wolbachia pipientis infects arthropod and nematode species worldwide, making it a key target for host biological control. Wolbachia-driven host reproductive manipulations, such as cytoplasmic incompatibility (CI), are credited for catapulting these intracellular bacteria to high frequencies in host populations. Positive, perhaps mutualistic, reproductive manipulations also increase infection frequencies, but are not well understood. Here, we identify molecular and cellular mechanisms by which Wolbachia influences the molecularly distinct processes of germline stem cell (GSC) self-renewal and differentiation. We demonstrate that wMel infection rescues the fertility of flies lacking the translational regulator mei-P26and is sufficient to sustain infertile homozygous mei-P26knockdown stocks indefinitely. Cytology revealed that wMel mitigates the impact of mei-P26 loss through restoring proper pMad, Bam, Sxl, and Orb expression. In Oregon R files with wild-type fertility, wMel infection elevates lifetime egg hatch rates. Exploring these phenotypes through dual-RNAseq quantification of eukaryotic and bacterial transcripts revealed that wMel infection rescues and offsets many gene expression changes induced by meiP26loss at the mRNA level. Overall, we show that wMel infection beneficially reinforces host fertility at mRNA, protein, and phenotypic levels, and these mechanisms may promote the emergence of mutualism and the breakdown of host reproductive manipulations.
General science-technology orientation, specific benefit–risk assessment frame, and public acceptance of gene drive biotechnology
28225X. Liu, C. L. Goldsmith, K. E. Kang, A. Vedlitz, Z. N. Adelman, L. W. Buchman, E. Heitman and R. F. Medina, Risk Analysis, 2023-10-23 15:04:31.
Abstract With limited understanding of most new biotechnologies, how do citizens form their opinion and what factors influence their attitudes about these innovations? In this study, we use gene drive biotechnology in agricultural pest management as an example and theoretically propose that given low levels of knowledge and awareness, citizens? acceptance of, or opposition to, gene drive is significantly shaped by two predisposition factors: individuals? general orientation toward science and technology, and their specific benefit-risk assessment frame. Empirically, we employ data collected from a recent US nationally representative public opinion survey (N = 1220) and conduct statistical analyses to test the hypotheses derived from our theoretical expectations. Our statistical analyses, based on various model specifications and controlling for individual-level covariates and state-fixed effects, show that citizens with a more favorable general orientation toward science and technology are more likely to accept gene drive. Our data analyses also demonstrate that citizens? specific gene drive assessment frame?consisting of a potential benefit dimension and a potential risk dimension, significantly shapes their attitudes as well?specifically, people emphasizing more on the benefit dimension are more likely to accept gene drive, whereas those who place more importance on the risk dimension tend to oppose it. We discuss contributions of our study and make suggestions for future research in the conclusion.
Incorporating ecology into gene drive modelling
28150J. Kim, K. D. Harris, I. K. Kim, S. Shemesh, P. W. Messer and G. Greenbaum, Ecology Letters, 26:S62-S80. 2023-10-23 11:37:54.
Abstract Gene drive technology, in which fast-spreading engineered drive alleles are introduced into wild populations, represents a promising new tool in the fight against vector-borne diseases, agricultural pests and invasive species. Due to the risks involved, gene drives have so far only been tested in laboratory settings while their population-level behaviour is mainly studied using mathematical and computational models. The spread of a gene drive is a rapid evolutionary process that occurs over timescales similar to many ecological processes. This can potentially generate strong eco-evolutionary feedback that could profoundly affect the dynamics and outcome of a gene drive release. We, therefore, argue for the importance of incorporating ecological features into gene drive models. We describe the key ecological features that could affect gene drive behaviour, such as population structure, life-history, environmental variation and mode of selection. We review previous gene drive modelling efforts and identify areas where further research is needed. As gene drive technology approaches the level of field experimentation, it is crucial to evaluate gene drive dynamics, potential outcomes, and risks realistically by including ecological processes.
Benefits and risks of gene drives for invasive plant management – the case for common tansy
28162L. Croghan, A. G. Smith, M. A. Tancos, N. O. Anderson and R. L. Becker, Frontiers in Agronomy, 5. 2023-10-20 12:05:59.
Invasive plants cause significant environmental and economic damage, but land managers have few control options. Common tansy (Tanacetum vulgare) is prevalent in many US states and is one of the most reported invasive plants in Minnesota. Controlling common tansy poses a challenge due to its extensive distribution and association with diverse plant communities. A gene drive is being explored as a genetic biocontrol method for the management of several non-native invasives, including common tansy in North America. Gene drives have emerged as a novel biotechnology application with potential to improve public health, promote conservation, and increase agricultural productivity. In common tansy, gene drives could be developed to target genes that would reduce or eliminate female fertility and consequently inhibit common tansy seed production. Using common tansy as an example, we outline risks associated with the use of gene drive technology for invasive plant control and explain how risks may be mitigated. Understanding potential benefits and risks associated with gene drives in the early stages of development is crucial. Mitigating risks, receiving stakeholder input, and navigating the regulatory environment will play an important role in gene drive development and deployment.
Gene drive in plants emerges from infancy
28152M. J. A. Awan, R. Z. Naqvi, I. Amin and S. Mansoor, Trends in Plant Science, 2023-10-18 11:43:35.
Selfish genetic elements (SGEs) display biased transmission to offspring. However, their breeding potential has remained obscure. Wang et al. recently reported a natural gene-drive system that can be harnessed to prevent hybrid incompatibility and to develop a synthetic gene-drive (SGD) system for crop improvement.
X-rays are as effective as gamma-rays for the sterilization of Glossina palpalis gambiensis Vanderplank, 1911 (Diptera: Glossinidae) for use in the sterile insect technique
28223B. A. Kaboré, A. Nawaj, H. Maiga, O. Soukia, S. Pagabeleguem, M. S. G. Ouédraogo/Sanon, M. J. B. Vreysen, R. L. Mach and C. J. de Beer, Scientific Reports, 13:17633. 2023-10-17 15:00:27.
An area-wide integrated pest management strategy with a sterile insect technique (SIT) component requires a radiation source for the sterilisation of male insects. Self-contained gamma irradiators, which were exclusively used in past SIT programmes, are now facing increasing constraints and challenges due to stringent regulations. As a potential alternative, new generation high output X-ray irradiators have been proposed. The feasibility of using X-ray irradiators was assessed by comparing the effects of both gamma- and X-ray irradiators on biological parameters of Glossina palpalis gambiensis (Vanderplank, 1911), that are important for SIT applications. The gamma irradiator Foss Model 812 and two X-ray irradiators, the Rad Source 2400 and the blood irradiator Raycell Mk2 were used. Glossina palpalis gambiensis males were exposed to radiation as pupae. A radiation dose of 110 Gy or above induced more than 97% sterility in females that mated with the irradiated males for all the irradiators. Adult emergence rate, flight propensity, survival and mating performance did not differ between gamma- and X-rays irradiators. These results suggest that irradiating pupae with a dose of 110 Gy is optimal for both gamma-and X-ray irradiators used in this study, to achieve a sterility of approximately 99%. Similar research on other tsetse species could gradually phase out the use of gamma-ray irradiators in favour of X-rays irradiators, especially for smaller SIT programmes.
Cleave and Rescue gamete killers create conditions for gene drive in plants
28140O. Georg, L. J. Michelle, I. Tobin and A. H. Bruce, bioRxiv, 2023.10.13.562303. 2023-10-14 10:23:38.
Gene drive elements promote the spread of linked traits, even when their presence confers a fitness cost to carriers, and can be used to change the composition or fate of wild populations. Cleave and Rescue (ClvR) drive elements sit at a fixed chromosomal position and include a DNA sequence-modifying enzyme such as Cas9/gRNAs (the Cleaver/Toxin) that disrupts endogenous versions of an essential gene, and a recoded version of the essential gene resistant to cleavage (the Rescue/Antidote). ClvR spreads by creating conditions in which those lacking ClvR die because they lack functional versions of the essential gene. We demonstrate the essential features of ClvR gene drive in the plant Arabidopsis thaliana through killing of gametes that fail to inherit a ClvR that targets the essential gene YKT61, whose expression is required in male and female gametes for their survival. Resistant (uncleavable but functional) alleles, which can slow or prevent drive, were not observed. Modeling shows plant ClvRs can be used to rapidly drive population modification or suppression. Possible applications in weed control, plant breeding and conservation are discussed.Competing Interest StatementThe authors have filed patent applications on ClvR and related technologies (U.S. Application No. 15/970,728 and No. 16/673,823).
Wolbachia enhances the survival ofDrosophila infected with fungal pathogens
28218J. Perlmutter, I., A. Atadurdyyeva, M. Schedl, E. and R. Unckless, L., bioRxiv, 2023.09.30.560320. 2023-10-11 14:49:32.
Wolbachia bacteria of arthropods are at the forefront of basic and translational research on multipartite host-symbiont-pathogen interactions. These microbes are vertically inherited from mother to offspring via the cytoplasm. They are the most widespread endosymbionts on the planet due to their infamous ability to manipulate the reproduction of their hosts to spread themselves in a population, and to provide a variety of fitness benefits to their hosts. Importantly, some strains of Wolbachia can inhibit viral pathogenesis within and between arthropod hosts. Mosquitoes carrying the wMel Wolbachia strain of Drosophila melanogaster have a greatly reduced capacity to spread viruses like dengue and Zika to humans. Therefore, Wolbachia are the basis of several global vector control initiatives. While significant research efforts have focused on viruses, relatively little attention has been given to Wolbachia-fungal interactions despite the ubiquity of fungal entomopathogens in nature. Here, we demonstrate that Wolbachia increase the longevity of their Drosophila melanogaster hosts when challenged with a spectrum of yeast and filamentous fungal pathogens. We find that this pattern can vary based on host genotype, sex, and fungal species. Further, Wolbachia correlates with higher fertility and reduced pathogen titers during initial fungal infection, indicating a significant fitness benefit. This study demonstrates Wolbachia’s role in diverse fungal pathogen interactions and determines that the phenotype is broad, but with several variables that influence both the presence and strength of the phenotype. These results enhance our knowledge of the strategies Wolbachia uses that likely contribute to such a high global symbiont prevalence.Importance Wolbachia bacteria of arthropods are at the forefront of global initiatives to fight arthropod-borne viruses. Despite great success in using the symbiont to fight viruses, little research has focused on Wolbachia-fungal interactions. Here, we find that Wolbachia of Drosophila melanogaster, the same strain widely used in antiviral initiatives, can also increase the longevity of flies systemically infected with a panel of yeast and filamentous fungal pathogens. The symbiont also partially increases host fertility and reduces fungal titers during early infection, indicating a significant fitness benefit. This represents a major step forward in Wolbachia research since its pathogen blocking abilities can now be extended to a broad diversity of another major branch of microbial life. This discovery may inform basic research on pathogen blocking and has potential translational applications in areas including biocontrol in agriculture.Competing Interest StatementThe authors have declared no competing interest.
Overriding Mendelian inheritance in Arabidopsis with a CRISPR toxin-antidote gene drive that impairs pollen germination
28101L. Yang, J. Bingke, C. Jackson and Q. Wenfeng, bioRxiv, 2023.10.10.561637. 2023-10-11 07:52:15.
Synthetic gene drives, inspired by natural selfish genetic elements, present transformative potential for disseminating traits that benefit humans throughout wild populations, irrespective of potential fitness costs. Here, we constructed a gene drive system called CRISPR-Assisted Inheritance utilizing NPG1 (CAIN), which employs a toxin-antidote mechanism in the male germline to override Mendelian inheritance in plants. Specifically, a gRNA-Cas9 cassette targets the essential No Pollen Germination 1 (NPG1) gene, serving as the toxin to block pollen germination. A recoded, CRISPR-resistant copy of NPG1 serves as the antidote, providing rescue only in pollen cells that carry the drive. To limit potential consequences of inadvertent release, we used self-pollinating Arabidopsis thaliana as a model. The drive demonstrated a robust 88-99% transmission rate over two successive generations, producing minimal resistance alleles that are unlikely to inhibit drive spread. Our study provides a strong basis for rapid genetic modification or suppression of outcrossing plant populations.Competing Interest StatementThe authors have declared no competing interest.
Wolbachia interferes with Zika virus replication by hijacking cholesterol metabolism in mosquito cells
28094B. Edwards, E. A.-O. X. Ghedin and D. A.-O. Voronin, Microbiology Spectrum, 2023-10-09 07:37:16.
Zika virus is a member of the arbovirus Flaviviridae family transmitted by Aedes mosquitos and it is associated with microcephaly in infants born to infected mothers. Wolbachia is an intracellular gram-negative alpha-proteobacteria that infects many species of arthropods, including mosquitos. The presence of Wolbachia in mosquitos has been shown to control the vector population and suppress arbovirus transmission. One mechanism of Wolbachia-mediated interference with virus replication is competition over host resources between Wolbachia and the virus. We hypothesize that cholesterol metabolism is involved in Wolbachia-mediated virus suppression due to its important role in Zika virus replication. In this study, we determined that Wolbachia impacted virus replication by altering cholesterol biosynthesis in Aedes albopictus C6/36 cells, diverting resources from the host cell mevalonate (MVA) pathway to fulfill the needs of the bacteria. This resulted in a decrease of total cholesterol, increased Wolbachia loads, and decreased viral titers. Inhibition of the MVA pathway using fluvastatin decreased total cholesterol and viral titers, mimicking the effects of Wolbachia on the virus in Wolbachia-free cells. We also found that Wolbachia-infected cells had depleted lipid droplets, the main component of which is cholesterol esters. We confirmed that cholesterol esterases were upregulated in response to virus infection in C6/36 cells. Functional analysis showed that alteration of cholesterol metabolism simulated Wolbachia-mediated inhibition of virus infection in C6/36 cells. Our study provides a mechanism behind Wolbachia-induced interference of arbovirus replication and could help advance strategies to control arbovirus pathogens in insect vectors and human infections. IMPORTANCE Arthropod-borne viruses are emerging pathogens that are spread widely by mosquitos. Zika virus is an arbovirus that can infect humans and be transmitted from an infected mother to the fetus, potentially leading to microcephaly in infants. One promising strategy to prevent disease caused by arboviruses is to target the insect vector population. Recent field studies have shown that mosquito populations infected with Wolbachia bacteria suppress arbovirus replication and transmission. Here, we describe how intracellular bacteria redirect resources within their host cells and suppress Zika virus replication at the cellular level. Understanding the mechanism behind Wolbachia-induced interference of arbovirus replication could help advance strategies to control arbovirus pathogens in insect vectors and human populations. FAU - Edwards, Brent
Expansions to the MGDrivE suite for simulating the efficacy of novel gene-drive constructs in the control of mosquito-borne diseases
28003J. B. Bennett, S. L. Wu, P. R. Chennuri, K. M. Myles and M. L. Ndeffo-Mbah, BMC Research Notes, 16:258. 2023-10-05 08:39:23.
The MGDrivE (MGDrivE 1 and MGDrivE 2) modeling framework provides a flexible and expansive environment for testing the efficacy of novel gene-drive constructs for the control of mosquito-borne diseases. However, the existing model framework did not previously support several features necessary to simulate some types of intervention strategies. Namely, current MGDrivE versions do not permit modeling of small molecule inducible systems for controlling gene expression in gene drive designs or the inheritance patterns of self-eliminating gene drive mechanisms. Here, we demonstrate a new MGDrivE 2 module that permits the simulation of gene drive strategies incorporating small molecule-inducible systems and self-eliminating gene drive mechanisms. Additionally, we also implemented novel sparsity-aware sampling algorithms for improved computational efficiency in MGDrivE 2 and supplied an analysis and plotting function applicable to the outputs of MGDrivE 1 and MGDrivE 2.
Mosquito Embryo Microinjection
27969R. A. Harrell, Cold Spring Harbor Protocols, 2023-10-03 07:27:01.
Genetically modified (GM) mosquitoes are an important tool in the fight against mosquito-borne disease, both indirectly through their use in research investigating host–pathogen interaction, mosquito olfaction, and anthropomorphic behavior and in future direct uses for suppression and possibly eradication through sterile insect technique (SIT) and/or gene-drive programs. Successful creation of GM mosquitoes depends on microinjection procedures that precisely deliver injection materials while causing as little damage to mosquito embryos as possible. Genetic modification reagents, such as transposon system components (vector plasmids, helper plasmids, and helper mRNA), and CRISPR–Cas9 components (guide RNAs, Cas9 protein, plasmids expressing Cas9 and/or guide RNAs, and donor plasmids used in homology-directed repair [HDR]), must be delivered into the preblastoderm embryo at the posterior end where the pole cells will form before cellularization occurs. Sharp needles that pierce the embryo easily are important tools in this procedure and work best when the embryos are not desiccated. The two main procedures for mosquito embryo microinjection involve injecting embryos under halocarbon oil or under aqueous solution.
The double-edged sword effect of expanding Wolbachia deployment in dengue endemic settings
28137M. G. Pavan, G. A. Garcia, M. R. David and R. Maciel-de-Freitas, The Lancet Regional Health - Americas, 27:100610. 2023-10-02 10:16:37.
We can use Brazil as a showcase to foresee and avoid a double-edged sword effect associated with Wolbachia releases. Insecticide resistance of native Ae. aegypti populations is spread worldwide (http://aedes.irmapper.com), and positive results should boost Wolbachia deployment in other dengue endemic settings around the world. Aedes aegypti populations are heterogeneous and nationwide releases of a Wolbachia strain whose genetic backcross belong to a specific locality would produce an unsought homogenization of vector populations. Aedes aegypti homogenisation at large geographic scales could impose additional undesirable consequences in the long-term by promoting genetic hitchhiking of traits such as higher vector competence, lower susceptibility to repellents and insecticides, or more avid host-seeking and biting behaviour. Available data has shown that ensuring adherence to local characteristics, specially a matching genetic between native and released mosquitoes, is critical to enhance the likelihood of achieving a faster introgression in the field, realizing cost and time savings over the globe. Probably there are a myriad of yet undiscovered traits beyond insecticide resistance that may influence vector local adaptation and would affect the success of released strains. Therefore, neglecting the genetic diversity in favour of centralising the rearing of mosquitoes with Wolbachia for nationwide releases could represent a drawback for future releases. Long-term studies regarding the consequences of releasing mosquitoes with homogenous genotypes in diverse ecological and epidemiological scenarios remain a critical research priority, essential for informed decision-making and sustainable management of mosquito-borne diseases.
Wolbachia-mediated resistance to Zika virus infection in Aedes aegypti is dominated by diverse transcriptional regulation and weak evolutionary pressures
27974E. C. Boehm, A. S. Jaeger, H. J. Ries, D. Castañeda, A. M. Weiler, C. C. Valencia, J. Weger-Lucarelli, G. D. Ebel, S. L. O’Connor, T. C. Friedrich, M. Zamanian and M. T. Aliota, PLOS Neglected Tropical Diseases, 17:e0011674. 2023-10-02 07:38:35.
A promising candidate for arbovirus control and prevention relies on replacing arbovirus-susceptible Aedes aegypti populations with mosquitoes that have been colonized by the intracellular bacterium Wolbachia and thus have a reduced capacity to transmit arboviruses. This reduced capacity to transmit arboviruses is mediated through a phenomenon referred to as pathogen blocking. Pathogen blocking has primarily been proposed as a tool to control dengue virus (DENV) transmission, however it works against a range of viruses, including Zika virus (ZIKV). Despite years of research, the molecular mechanisms underlying pathogen blocking still need to be better understood. Here, we used RNA-seq to characterize mosquito gene transcription dynamics in Ae. aegypti infected with the wMel strain of Wolbachia that are being released by the World Mosquito Program in Medellín, Colombia. Comparative analyses using ZIKV-infected, uninfected tissues, and mosquitoes without Wolbachia revealed that the influence of wMel on mosquito gene transcription is multifactorial. Importantly, because Wolbachia limits, but does not completely prevent, replication of ZIKV and other viruses in coinfected mosquitoes, there is a possibility that these viruses could evolve resistance to pathogen blocking. Therefore, to understand the influence of Wolbachia on within-host ZIKV evolution, we characterized the genetic diversity of molecularly barcoded ZIKV virus populations replicating in Wolbachia-infected mosquitoes and found that within-host ZIKV evolution was subject to weak purifying selection and, unexpectedly, loose anatomical bottlenecks in the presence and absence of Wolbachia. Together, these findings suggest that there is no clear transcriptional profile associated with Wolbachia-mediated ZIKV restriction, and that there is no evidence for ZIKV escape from this restriction in our system.
Situating the social sciences in responsible innovation in the global south: the case of gene drive mosquitoes
28148K. Ledingham, C. Opesen, S. Hartley and S. Neema, Journal of Responsible Innovation, 10:2264100. 2023-10-01 11:32:46.
There has been growing attention in recent years on the potential reconfiguration of responsible innovation (RI) to increase its relevance for global challenges in the Global South. This reconfiguration will require a broad and empowered role for social scientists. Yet RI has been preoccupied with public and stakeholder inclusion, rather than social science inclusion. We probe this gap through a case study of the social sciences in the development of gene drive mosquitoes for malaria control in Mali and Uganda. Our data reveals potential diverse roles and future research agendas for the social sciences. We outline some challenges facing the social sciences in this space and ways to promote and support them. Lastly, we argue that RI?s predilection for reflexive and critical social science obscures a richer repertoire of social science roles that are an imperative and fundamental part of efforts to address global challenges in the Global South.
Next-generation genetic sexing strain establishment in the agricultural pest Ceratitis capitata
27972S. Davydova, J. Liu, N. Kandul, P., W. E. Braswell, O. Akbari, S. and A. Meccariello, bioRxiv, 2023.09.29.560088. 2023-10-01 07:32:11.
Tephritid fruit fly pests pose an increasing threat to the agricultural industry due to their global dispersion and a highly invasive nature. Here we showcase the feasibility of an early-detection SEPARATOR sex sorting approach through using the non-model Tephritid pest, Ceratitis capitata. This system relies on female-only fluorescent marker expression, accomplished through the use of a sex-specific intron of the highly-conserved transformer gene from C. capitata and Anastrepha ludens. The herein characterized strains have 100% desired phenotype outcomes, allowing accurate male-female separation during early development. Overall, we describe an antibiotic and temperature-independent sex-sorting system in C. capitata, which, moving forward, may be implemented in other non-model Tephritid pest species. This strategy can facilitate the establishment of genetic sexing systems with endogenous elements exclusively, which, on a wider scale, can improve pest population control strategies like sterile insect technique.Competing Interest StatementO.S.A is a founder of Agragene, Inc. and Synvect, Inc. with equity interest. N.P.K is a founder of Synvect, Inc. with equity interest. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict-of-interest policies. All other authors declare no competing interests
Supergenes as drivers of ant evolution
27997M. Chapuisat, Myrmecological News, 33:1-18. 2023-09-30 08:25:16.
Ants show striking diversity in social organization, raising major questions on the proximate and ultimate causes of such variation. The shift from one-queen (= monogyne) societies to multi-queen (= polygyne) societies has long been viewed as a phenotypically plastic response to ecological and social conditions. In contrast to this view, in five independent ant lineages, alternative forms of colony social organization are controlled by supergenes. Supergenes are large groups of linked genes determining compound adaptive phenotypes, like colour morphs, ecotypes, or social forms. In the best-studied socially polymorphic ant species, Solenopsis invicta and Formica selysi, a supergene variant (= haplotype) is exclusively found in multi-queen colonies and does not recombine with the alternative haplotype. How did such supergenes spread? Supergenes might be favoured by natural selection because they link co-adapted alleles that are beneficial in one social form. The absence of recombination ensures that these alleles are transmitted together and prevents maladaptive combinations between alleles. However, supergenes can also spread selfishly, by distorting Mendelian transmission in their favour. Non-recombining regions are indeed prone to harbour selfish genetic elements, which are typically formed by tight linkage of a killer gene, or toxin, and a rescue gene, or antidote. Strikingly, the social supergene haplotypes associated with multi-queen colonies of ants selfishly favour their own transmission by causing gene drive through distinct mechanisms. In S. invicta, the “polygyne” haplotype causes a green-beard effect: Workers that carry this haplotype kill queens that lack it. In F. selysi, the “polygyne” haplotype is a maternal-effect killer: Offspring of mothers that carry this selfish haplotype fail to hatch when they do not inherit a copy of the haplotype. Overall, the ants’ social supergenes induce unexpected combinations of adaptive and detrimental effects across levels of biological organization. On the one hand, they coordinate individual and colony-level traits, such as queen number, mating system, and dispersal. On the other hand, supergenes cause selfish gene drive and lethal effects due to accumulation of deleterious mutations. The evolutionary dynamics of these large groups of linked genes is therefore particularly complex, and explaining their long-term maintenance is challenging. I argue that social supergenes can be drivers of ant evolution because they spread selfishly and show lethal effects. Therefore, an understanding of the unusual properties of the underlying genetic system is needed to explain variation in colony queen number.
Testing a candidate meiotic drive locus identified by pool sequencing
27983D. A. Barbash, B. Jin, K. H. C. Wei and A.-M. Dion-Côté, G3 Genes|Genomes|Genetics, 2023-09-28 07:56:24.
Meiotic drive biases the transmission of alleles in heterozygous individuals, such that Mendel’s law of equal segregation is violated. Most examples of meiotic drive have been discovered over the past century based on causing sex-ratio distortion or the biased transmission of easily scoreable genetic markers that were linked to drive alleles. More recently, several approaches have been developed that attempt to identify distortions of Mendelian segregation genome-wide. Here we test a candidate female meiotic drive locus in Drosophila melanogaster, identified previously as causing a ∼54:46 distortion ratio using sequencing of large pools of backcross progeny. We inserted fluorescent visible markers near the candidate locus and scored transmission in thousands of individual progeny. We observed a small but significant deviation from the Mendelian expectation, however it was in the opposite direction to that predicted based on the original experiments. We discuss several possible causes of the discrepancy between the two approaches, noting that subtle viability effects are particularly challenging to disentangle from potential small-effect meiotic drive loci. We conclude that pool sequencing approaches remain a powerful method to identify candidate meiotic drive loci, but that genotyping of individual progeny at early developmental stages may be required for robust confirmation.
A natural gene drive element confers speciation in rice
28000Y. Li, S. Liu and R. Shen, Chinese Science Bulletin, 68:3400-3402. 2023-09-27 08:30:59.
For a long time, although many important advances have been made in the field of rice hybrid sterility, the specific molecular mechanism behind the "killer-protector"/ "poison-antidote" model has been unclear. Recently, the team of Academician Wan Jianmin of Nanjing Agricultural University identified a major locus RHS12 controlling pollen sterility of indica-japonica hybrids. This site belongs to the same locus as the recently cloned pf12 and Se[16,17]. Genetic analysis revealed that RHS12 consists of two closely linked genes, iORF3/DUYAO and iORF4/JIEYAO. These two genes are commonly found in indica rice genome, but not in some japonica rice genomes. iORF3 (DUYAO) encodes a poison protein localized in mitochondria. DUYAO interacts with OsCOX11, a core functional protein in the mitochondrial respiratory chain, to cause mitochondrial dysfunction and induce programmed cell death (program cell death, PCD) leading to pollen abortion. iORF4 (JIEYAO) encodes an antidote protein that interacts with the DUYAO protein to bring DUYAO to the autophagosome for degradation, thereby releasing OsCOX11 for normal pollen development (Fig. 1). Therefore, during the pollen development of indica-japonica hybrids, the pollen of japonica type without this pair of genes was selectively aborted, while the pollen of indica type with this pair of genes developed normally. For the first time, this study completely and clearly clarified the mechanism of RHS12 regulating rice hybrid sterility from the genetic, cellular and molecular levels, and achieved a major breakthrough in this field.
Engineered and natural gene drives: mechanistically the same, yet not same in kind
27995R. F. Medina and J. Kuzma, Nature Communications, 14:5994. 2023-09-26 08:18:08.
We propose the use of the terms natural gene drive (NGD) and engineered gene drive (EGD) arguing against James et al.1, who think both should be included within the term “gene drive”, based on their mechanistic similarities. Thanks to CRISPR-Cas-based gene editing, engineered gene drive has suddenly become feasible as a potential cost-effective pest control tool that could help us resolve wicked challenges2,3 . In nature, several organisms harbor genes that “selfishly” drive themselves into populations. This natural gene drive uses similar mechanisms to the ones use today to drive engineered genes into laboratory populations4 article we disagree with James et al.1 .In this who have recently proposed that because natural and engineered gene drives are mechanistically indistinguishable from a molecular standpoint, they should both be referred as “gene drives” because “a gene drive is a gene drive.” We instead propose that two terms be used to distinguish between natural and engineered gene drives, we second Wells and Steinbrecher5 arguments, and propose to use the terms natural gene drive (NGD) and engineered gene drive (EGD).
Contact Us
Alex Sullivan
Foundation for the
National Institutes of Health
geneconvenevi@fnih.org