Scholarly Literature
This is an aggregation of scholarly literature from peer-reviewed journals, bioRxiv , medRxiv and arXiv preprint servers focused on natural and engineered selfish genetic elements and genetic biocontrol. New citations are added as they appear. This content is intended for anyone interested in the scholarly literature on gene drive and genetic biocontrol.
A predatory gene drive for targeted control of self-transmissible plasmids
34734Ryan Tsoi et al., Science Advances, 11. 2025-04-03 17:09:42.
Suppressing plasmid transfer in microbial communities has profound implications due to the role of horizontal gene transfer (HGT) in spreading and maintaining diverse functional traits such as metabolic functions, virulence factors, and antibiotic resistance. However, existing tools for inhibiting HGT are limited in their modes of delivery, efficacy, and scalability. Here, we present a versatile denial-of-spread (DoS) strategy to target and eliminate specific conjugative plasmids. Our strategy exploits retrotransfer, whereby an engineered DoS plasmid is introduced into host cells containing a target plasmid. Acting as a predatory gene drive, DoS propagates itself at the expense of the target plasmid, through competition or active elimination. Once the target plasmid is eradicated, DoS is removed via induced plasmid suicide, resulting in a community containing neither plasmid. The strategy is tunable and scalable for various conjugative plasmids, different mechanisms of plasmid inheritance interruption, and diverse environmental contexts. DoS represents a new tool for precise control of gene persistence in microbial communities.
Global asymptotic stability in a delay stage structured model for mosquito population suppression
34720Huang, Mg., Yu, Js., Applied Mathematics, 40:112-136. 2025-03-31 14:42:25.
A promising avenue to control mosquito-borne diseases such as dengue, malaria, and Zika involves releasing male mosquitoes carrying the bacterium Wolbachia in wild areas to drive female sterility by a mechanism called cytoplasmic incompatibility (CI). In this work, we initiate a preliminary assessment of how the combined impact of dispersal, incomplete CI and mating competitiveness on mosquito population suppression by a delay differential equation model. Our theoretical analyses indicate that the immigration of eggs plays a significant role in the suppression dynamics. For the case without egg immigration, we identify a threshold dispersal rate v* of adult mosquitoes, threshold CI density ξ*, and threshold release ratio r*. A successful mosquito suppression would be established only when v < v*, ξ > ξ*, and r(t) ≥ r* uniformly. The immigration of eggs causes the threshold dynamics to be invalid, and warns an absolute failure of population suppression. The monotonicity of the adult steady-state in the dispersal rate and CI intensity indicates that choosing a suitable Wolbachia strain with strong CI intensity, or bringing down the dispersal rate of mosquitoes by blocking the suppression zones is a feasible strategy to obtain a better suppression level.
Exploiting Wolbachia as a Tool for Mosquito-Borne Disease Control: Pursuing Efficacy, Safety, and Sustainability
34677Moretti, R., Lim, J. T., Ferreira, A. G. A., et al, Pathogens, 14:285. 2025-03-28 09:41:16.
Despite the application of control measures, mosquito-borne diseases continue to pose a serious threat to human health. In this context, exploiting Wolbachia, a common symbiotic bacterium in insects, may offer effective solutions to suppress vectors or reduce their competence in transmitting several arboviruses. Many Wolbachia strains can induce conditional egg sterility, known as cytoplasmic incompatibility (CI), when infected males mate with females that do not harbor the same Wolbachia infection. Infected males can be mass-reared and then released to compete with wild males, reducing the likelihood of wild females encountering a fertile mate. Furthermore, certain Wolbachia strains can reduce the competence of mosquitoes to transmit several RNA viruses. Through CI, Wolbachia-infected individuals can spread within the population, leading to an increased frequency of mosquitoes with a reduced ability to transmit pathogens. Using artificial methods, Wolbachia can be horizontally transferred between species, allowing the establishment of various laboratory lines of mosquito vector species that, without any additional treatment, can produce sterilizing males or females with reduced vector competence, which can be used subsequently to replace wild populations. This manuscript reviews the current knowledge in this field, describing the different approaches and evaluating their efficacy, safety, and sustainability. Successes, challenges, and future perspectives are discussed in the context of the current spread of several arboviral diseases, the rise of insecticide resistance in mosquito populations, and the impact of climate change. In this context, we explore the necessity of coordinating efforts among all stakeholders to maximize disease control. We discuss how the involvement of diverse expertise—ranging from new biotechnologies to mechanistic modeling of eco-epidemiological interactions between hosts, vectors, Wolbachia, and pathogens—becomes increasingly crucial. This coordination is especially important in light of the added complexity introduced by Wolbachia and the ongoing challenges posed by global change.
Adjacent spillover efficacy of Wolbachia for control of dengue: emulation of a cluster randomised target trial
34679Lim, J.T., Mailepessov, D., Chong, C.S. et al., BMC Medicine, 23. 2025-03-28 08:29:31.
Matings between male Aedes aegypti mosquitoes infected with wAlbB strain of Wolbachia and wild-type females yield non-viable eggs, thereby suppressing Ae. aegypti abundance in the field. We evaluated the spillover efficacy of releasing wAlbB-infected Ae. aegypti male mosquitoes to suppress dengue in sites adjacent to release sites (spillover sites). The protocol of a two-arm cluster-randomised test-negative controlled trial (cRCT) was specified and emulated using a nationally representative dengue test-negative/positive database of 454,437 individuals reporting for febrile illness to primary or secondary care in public healthcare institutions. Spillover intervention sites were defined by geolocating locations which were adjacent to, i.e. shared geographical borders with, actual Wolbachia intervention sites. We built a cohort of individuals who resided in spillover sites versus a comparator control group who resided in sites which did not receive Wolbachia interventions. We emulated a constrained randomisation protocol used in cRCTs to balance dengue risk between spillover and control arms in the pre-intervention period. We matched individuals reporting for testing in intervention and control groups by calendar time and a high-dimensional battery of sociodemographic, environmental and anthropogenic variables. Intention-to-treat analysis was conducted to estimate the protective efficacy against dengue given spillover Wolbachia exposure. The final cohort consisted of 2354 matched individuals residing in Wolbachia spillover and control sites for at least 3 months in the study period. Compared to the controls, individuals residing in spillover sites for 3 or more months were associated with a 45% (OR: 0.55, 95% CI: 0.42‒0.74) reduction in risk of contracting dengue. Higher durations of spillover Wolbachia exposure also modestly increased protective efficacies. Compared to the control arm, the proportion of virologically confirmed dengue cases was lower in the spillover arm overall and across each subgroup. Protective efficacies were found across all years, age and sex subgroups. Our results demonstrated the potential of Wolbachia-mediated sterility for reducing the risk of contracting dengue even in sites which were not directly treated by the intervention.
Challenges in developing a split drive targeting dsx for the genetic control of the invasive malaria vector Anopheles stephensi
34659Larrosa-Godall, M., Ang, J.X.D., Leftwich, P.T. et al., Parasites & Vectors, 18. 2025-03-25 09:18:22.
Anopheles stephensi is a competent malaria vector mainly present in southern Asia and the Arabian Peninsula. Since 2012, it has invaded several countries of eastern Africa, creating an emerging risk of urban transmission. Urgent efforts are required to develop novel and more efficient strategies for targeted vector control. CRISPR/Cas9-based homing gene drives have been proposed as attractive alternative strategies. Gene drives have the potential to spread a desired trait through a population at higher rates than via normal Mendelian inheritance, even in the presence of a fitness cost. Several target genes have been suggested and tested in different mosquito vector species such as Anopheles gambiae and Aedes aegypti. Several promising suppression drives have been developed in An. gambiae that target the sex determination gene doublesex (dsx). In this study, a geographically confineable gene drive system targeting dsx was developed (dsxgRNA). Here, a transgenic line which expresses Cas9 under the control of the endogenous zpg promoter was generated. Separately a transgenic line which expresses a gRNA targeting the female specific exon of dsx was inserted into that same target site. The reproductive fitness of males and females heterozygous and homozygous for this element was determined. A series of experimental crosses was performed to combine the two elements and assess the homing rate of the dsx element in a split drive system. The drive was able to home in a super-Mendelian rate comparable to those obtained by an autonomous drive in this species. Although inheritance rates as high as 99.8% were observed, potentially providing very potent gene drive, dominant effects on male and female fertility were observed, which would be sufficient to hinder spread of such a drive. Molecular analysis indicated that the gRNA expressing insertion disrupted normal splicing of dsx. These results should be considered when proposing the viability of dsx as a target gene for a population suppression gene drives in Anopheles stephensi. Although high homing rates were observed, the fitness defects found in both males and females carrying the transgene would likely prohibit this drive from functioning in the field.
Functional constraints of wtf killer meiotic drivers
34646Nidamangala Srinivasa A., Campbell S., Venkatesan S., et al., PLOS Genetics, 21. 2025-03-21 14:59:22.
Diploid organisms, such as humans, have two copies of most genes. Only one copy, however, is transmitted through gametes (e.g., sperm and egg) to any given offspring. Alternate copies of the same gene are expected to be equally represented in the gametes, resulting in random transmission to the next generation. However, some genes can “cheat” to be transmitted to more than half of the gametes, often at a cost to the host organism. Killer meiotic drivers are one such class of cheater genes that act by eliminating gametes lacking the driver. In this work, we studied the wtf family of killer meiotic drivers found in fission yeasts. Each wtf driver encodes a poison and an antidote protein to specifically kill gametes that do not inherit the driver. Through analyzing a large suite of diverse natural and engineered mutant wtf genes, we identified multiple properties—such as poison self-assembly and poison-antidote co-assembly—that can constrain poison toxicity and antidote rescue. These constraints could influence the evolution of wtf genes. Additionally, we discovered several incompatible wtf poison-antidote pairs, demonstrating expanded potential for self-killing wtf alleles. Such alleles could potentially arise spontaneously in populations cause infertility.
Mark-Release-Recapture of Packed and Shipped Aedes aegypti with Wolbachia: Implications for Conducting Remote Incompatible Insect Technique Programs
34640Ohm, J. R., Lynd, A., McGowan, A., et al., The American Journal of Tropical Medicine and Hygiene, 2025-03-21 14:44:30.
Male mosquitoes containing the endosymbiont Wolbachia (Wb+) can be used as a tool to suppress wild mosquito populations through a technique termed incompatible insect technique (IIT). IIT programs reduce wild mosquitoes via incompatible matings between released males and wild females to reduce the number of viable offspring produced in the next generation. Successful programs rely on regular release of incompatible males to outcompete wild males for female mates. Past IIT programs have relied on local production of Wb+ males to support regular releases of incompatible males. Here, we evaluated the survival and dispersal of packed and shipped Wb+ Aedes aegypti males in mark-release-recapture studies at a release site in the British Virgin Islands (BVI), separated by over 3,600 miles from the centralized production facility. Released mosquitoes were recaptured using BG-Sentinel 2 traps collected daily for up to 7 days after release. Wb+ male mosquitoes packed and shipped from a centralized production facility performed similarly to males that were locally reared in the BVI in survival, dispersal, and recapture rates. Our results support the conclusion that packing and shipping live Wb+ male mosquitoes does not impact their ability to survive and disperse in release sites and suggests that IIT mosquito control programs can feasibly be conducted nearly anywhere in the world without the need for local mosquito production facilities.
Gene drives. Technologies for spreading genetic modifications in populations. TAB-Fokus
34652König, H., Kolleck, A., Sauter, A., TAB-Fokus, 48. 2025-03-21 07:04:16.
Gene drives have the potential to help solve major challenges, including the fight against invasive species or vector-borne diseases such as malaria. These hopes are offset by technical and scientific challenges as well as environmental risks. The policy brief TAB-Fokus no. 48 on the opportunities and risks of a technology for spreading desirable traits in populations summarises the most important results of the TA project for the German Bundestag on four pages (and is also available as a web version - see relation in KITopen). Detailed results can be found in the final report - see relation in KITopen).
Engineering drive–selection balance for localized population suppression with neutral dynamics
34597Willis, K., and Burt, A., Proceedings of the National Academy of Sciences, 122. 2025-03-18 10:29:28.
While the release of sterile males has been highly successful in suppressing some pest populations, it is impractical for many species due to the males disappearing after a single generation, necessitating large, repeated releases to maintain sufficient impact. Synthetic gene drives promise more efficient approaches since they can increase in frequency from rare, yet this also allows them to spread across a landscape, which may not always be desired. Between these two extremes are selectively neutral genetic constructs which persist at the frequency they are released, offering the potential for efficient suppression that remains localized. One way to achieve this would be to have perfect balance, at all construct frequencies, between gene drive increasing frequency and selection decreasing it. Here, we describe a way to closely approximate this balance using a toxin–antidote genetic construct that causes recessive lethality or sterility, encodes a genomic editor that makes dominant lethal or sterile edits in the genome, and provides protection against the action or consequences of the editing. Computer modeling shows that this design can be 100-fold more efficient than sterile males, increasing to 1,000-fold when released alongside a genetic booster. We describe designs for CRISPR-based molecular construction, including options that avoid using recoded genes as antidotes.
Gene drive: communication, hype, and the publics
34577Boëte, C., Journal of Medical Entomology, 2025-03-12 16:35:04.
Engineered gene drive (EGD) systems are probably the most high-tech approach considered for their potential role in the control of vector-borne diseases. Interestingly, the rhetoric around it often goes along with a negative presentation of the current “conventional” tools and exaggerated promises about EGD themselves, leading to a situation of hype.
wStri spread dynamics in Nilaparvata lugens via discrete mathematical models
34574Zheng, B., Yang, H., Elaydi, S. et al., Journal of Mathematical Biology, 90. 2025-03-12 16:30:16.
Wolbachia, an intracellular bacterium, is well-known for inducing cytoplasmic incompatibility, which has become a promising and environmentally sustainable strategy for controlling pest populations. The strain wStri, specifically identified in Nilaparvata lugens (brown planthopper), has shown potential for such biocontrol applications. In this study, we develop a comprehensive discrete mathematical model to analyze the dynamics of wStri spread in a mixed population of wStri-infected, wLug-infected, and uninfected Nilaparvata lugens under both constant and periodically varying environmental conditions. Under a constant environment, the model identifies the critical threshold necessary for the successful establishment of wStri within the population. Our analysis reveals that the model exhibits a strong Allee effect, where a population must exceed a certain critical density-the Allee threshold-for the wStri strain to persist and spread. Below this threshold, the wStri strain is likely to be eliminated, failing in pest control efforts. When the environment varies periodically, the model transforms into a non-autonomous periodic discrete model, introducing additional complexity. In this scenario, we derive sufficient conditions that ensure the composition of finitely many Allee maps continues to function as an Allee map. Furthermore, we prove that a unique periodic orbit exists within such a periodic environment. This orbit is characterized as unstable and acts as a threshold, determining whether wStri will establish itself in the population or die out over time. The findings from this model provide critical insights into the conditions under which wStri can be effectively used to control Nilaparvata lugens, particularly in environments that are not constant but fluctuate periodically. These insights have significant implications for the practical deployment of Wolbachia-based biocontrol methods in pest management strategies.
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.
CRISPR/Cas9 Genome Editing in the Diamondback Moth: Current Progress, Challenges, and Prospects
34556Asad, M., Chang, Y., Liao, J., & Yang, G., International Journal of Molecular Sciences, 26:1515. 2025-03-04 11:34:07.
The development of site-specific genome-editing tools like CRISPR (clustered regularly interspaced short palindromic repeat) and its associated protein, Cas9, is revolutionizing genetic engineering with its highly efficient mechanism, offering the potential for effective pest management. Recently, CRISPR/Cas9 gene-editing has been extensively utilized in the management of the diamondback moth, Plutella xylostella (L.), a highly destructive pest of vegetable crops, for different purposes, such as gene function analysis and genetic control. However, the progress related to this gene-editing tool in P. xylostella has not yet been summarized. This review highlights the progress and applications of CRISPR/Cas9 in uncovering the genes critical for development, reproduction, and insecticide resistance in P. xylostella. Moreover, the progress related to the CRISPR/Cas9 gene drive for population suppression and modifications has also been discussed. In addition to the significant progress made, challenges such as low germline editing efficiency and limited homology-directed repair remain obstacles to its widespread application. To address these limitations, we have discussed the different strategies that are anticipated to improve the efficiency of CRISPR/Cas9, paving the way to it becoming a pivotal tool in sustainable pest management. Therefore, the present review will help researchers in the future enhance the efficiency of the CRISPR/Cas9 system and use it to manage the diamondback moth.
Engineering gene drive docking sites in a haplolethal locus in Anopheles gambiae
34552Andrea L Smidler, Eryney A Marrogi, Sean Scot, et al., bioRxiv, 2025-03-04 11:03:46.
Gene drives are selfish genetic elements which promise to be powerful tools in the fight against vector-borne diseases such as malaria. We previously proposed population replacement gene drives designed to better withstand the evolution of resistance by homing through haplolethal loci. Because most mutations in the wild-type allele that would otherwise confer resistance are lethal, only successful drive homing permits the cell to survive. Here we outline the development and characterization of two ΦC31-Recombination mediated cassette exchange (RMCE) gene drive docking lines with these features in Anopheles gambiae, a first step towards construction of robust gene drives in this important malaria vector. We outline adaption of the technique HACK (Homology Assisted CRISPR knockin) to knock-in two docking site sequences into a paired haplolethal-haplosufficient (Ribosome-Proteasome) locus, and confirm that these docking lines permit insertion of drive-relevant transgenes. We report the first anopheline proteasome knockouts, and identify ribosome mutants that reveal a major hurdle that such designs must overcome to develop robust drives in the future. Although we do not achieve drive, this work provides a new tool for constructing future evolution-robust drive systems and reveals critical challenges that must be overcome for future development of gene drives designed to target haplolethal loci in anophelines and, potentially, other metazoans.
Reenacting a mouse genetic evolutionary arms race in yeast reveals that SLXL1/SLX compete with SLY1/2 for binding to Spindlins
34550M.F. Arlt,A.N. Kruger,C.M. Swanepoel,& J.L. Mueller, Proceedings of the National Academy of Sciences, 122. 2025-03-04 10:54:14.
In the house mouse, an evolutionary arms race between proteins encoded by the X-linked Slxl1/Slx and Y-linked Sly gene families during spermatogenesis can distort offspring sex ratio, but how these proteins compete remains unknown. We report how SLXL1/SLX competes with SLY1/SLY2 by demonstrating their dose-dependent competitive binding to Spindlins, the key protein domains and rapidly evolving residues and exons that drive the competition, and how the competition is likely between complex multimers. Our findings have broad implications for the mechanics of evolutionary arms and how competition between sex chromosomes influences X- versus Y-sperm fitness and sex ratio.
RNA-guided nucleases enable a gene drive of insertion sequences in plasmids
34547Kepler S. Mears, Fernando W. Rossine, Natalia Quinones-Olvera, et al., bioRxiv, 2025-03-04 10:40:44.
Mobile genetic elements (MGEs) and the interactions between them are a major source of evolutionary innovation. Insertion sequences, the simplest MGEs usually encoding only the necessary genes for transposition and maintenance, are widespread in bacterial genomes, and are particularly common in plasmids. Plasmids, self-replicating extrachromosomal DNA elements, often exist in multiple copies imparting a stochastic barrier to the fixation of an insertion sequence by limiting the proportion of the plasmid population harboring the IS. In this work we demonstrate that to overcome this, the IS200/605 family of insertion sequences utilizes programmable RNA guided nucleases as gene drive to spread the IS through the plasmid population. TnpB, the likely ancestor of Cas12, records the specific insertion site of the IS in its RNA guide to prevent loss of the IS during transposition. When introduced to a plasmid TnpB will be reprogrammed to target and cleave IS-plasmids, resulting in biased replication of IS+ plasmids. Furthermore, the gene drive activity is critical for the IS to invade high copy plasmid populations. Because TnpB can only be mobilized between microbes on other mobile genetic elements, this advantage to fixing in plasmids may help explain the prevalence of TnpB across the tree of life. More generally, the unique pressures arising from movement between genetic contexts with different multiplicities shapes the evolution of strategies for MGE spread.
Wolbachia-based mosquito control: Environmental perspectives on population suppression and replacement strategies
34543Bhattacharyya, J., Roelke, D.L., Acta Tropica, 262. 2025-02-25 10:59:30.
Mosquito-borne diseases pose a significant threat to global health, and traditional mosquito control methods often fall short of effectiveness. A promising alternative is the biological control strategy of transinfecting mosquitoes with Wolbachia, a bacterium capable of outcompeting harmful pathogens and reducing the ability of mosquitoes to transmit diseases. However, Wolbachia infections are sensitive to abiotic environmental factors such as temperature and humidity, which can affect their densities in mosquitoes and, consequently, their ability to block pathogens. This review evaluates the effectiveness of different Wolbachia strains transinfected into mosquitoes in reducing mosquito-borne diseases. It explores how Wolbachia contributes to mosquito population control and pathogen interference, highlighting the importance of mathematical models in understanding Wolbachia transmission dynamics. Additionally, the review addresses the potential impact on arboviral transmission and the challenges posed by environmental fluctuations in mosquito control programs.
Exploiting venom toxins in paratransgenesis to prevent mosquito-borne disease
34533French, S., Da Silva, R., Storm, J. et al., Parasites & Vectors, 18. 2025-02-21 11:33:53.
Mosquitoes are responsible for the transmission of numerous pathogens, including Plasmodium parasites, arboviruses and filarial worms. They pose a significant risk to public health with over 200 million cases of malaria per annum and approximately 4 billion people at risk of arthropod-borne viruses (arboviruses). Mosquito populations are geographically expanding into temperate regions and their distribution is predicted to continue increasing. Mosquito symbionts, including fungi, bacteria and viruses, have desirable traits for mosquito disease control including spreading horizontally and vertically through mosquito populations and potentially colonising multiple important vector species. Paratransgenesis, genetic modification of mosquito symbionts with effectors to target the pathogen rather than the vector, is a promising strategy to prevent the spread of mosquito-borne diseases. A variety of effectors can be expressed but venom toxins are excellent effector candidates because they are target specific, potent and stable. However, the only toxins to be explored in mosquito paratransgenesis to date are scorpine and mutated phospholipase A2. To enhance the scope, effectiveness and durability of paratransgenesis, an expanded arsenal of effectors is required. This review discusses other potential toxin effectors for future paratransgenesis studies based on prior in vitro and in vivo antiparasitic and antiviral studies and highlights the need for further research and investment in this area. In terms of mosquito-borne diseases, paratransgenesis strategies have been developed to target Plasmodium. We postulate the potential to apply this principle to target arboviruses using antiviral toxin effectors.
Antagonistic kinesin-14s within a single chromosomal drive haplotype
34531Meghan J. Brady, Anjali Gupta, Jonathan I. Gent, et al., bioRxiv, 2025-02-21 10:31:41.
In maize, there are two meiotic drive systems that operate on large tandem repeat arrays called knobs that are found on chromosome arms. One meiotic drive haplotype, Abnormal chromosome 10 (Ab10), encodes two kinesin proteins that interact with two distinct tandem repeat arrays in a sequence-specific manner to confer meiotic drive. The kinesin KINDR associates with knob180 repeats while the kinesin TRKIN associates with TR-1 repeats. Prior data show that meiotic drive is conferred primarily by the KINDR/knob180 system, with the TRKIN/TR-1 system having little or no role. The second meiotic drive haplotype, K10L2, shows low levels of meiotic drive and only encodes the TRKIN/TR-1 system. Here we used long-read sequencing to assemble the K10L2 haplotype and showed that it has strong homology to an internal portion of the Ab10 haplotype. We also carried out CRISPR mutagenesis of Trkin to test the role of Trkin on Ab10 and K10L2. The data indicate that the Trkin gene on Ab10 does not improve drive or fitness but instead has a weak deleterious effect when paired with a normal chromosome 10. The deleterious effect is more severe when Ab10 is paired with K10L2: in this context functional Trkin on either chromosome nearly abolishes Ab10 drive. We modeled the effect of Trkin on Ab10 and found it should not persist in the population. We conclude that Trkin either confers an advantage to Ab10 in untested circumstances or that it is in the process of being purged from the Ab10 population.
Implications of successive blood feeding on Wolbachia-mediated dengue virus inhibition in Aedes aegypti mosquitoes
34529Rebecca M. Johnson, Mallery I. Breban, Braiya L. Nolan, et al., bioRxiv, 2025-02-21 10:22:32.
Dengue virus (DENV) is a mosquito-borne virus that poses a continued and increasing threat to public health. A promising strategy to mitigate the burden of DENV is introgression of the virus-inhibiting Wolbachia pipientis bacterium into Aedes aegypti populations in the field. While previous studies on Wolbachia-mediated virus inhibition have typically assessed viral replication following a single bloodmeal, the main vector of DENV, Ae. aegypti, feeds frequently, often biting multiple hosts per gonotrophic cycle and promptly attempting to refeed following egg laying. Previously, we demonstrated that successive blood feeding reduces the extrinsic incubation period (EIP) and shortens the time it takes for a mosquito to be able to transmit viruses to a new host. With this in mind, we investigated the impact of successive blood meals on DENV serotype 2 (DENV-2) in Ae. aegypti in the presence or absence of Wolbachia (wAlbB and wMelM). We found that both WT and Wolbachia transinfected had increased DENV-2 dissemination 7 days post-infection as well as higher body titers of DENV-2 in the double-fed groups. Using these empirical data in a binomial regression model, we estimated that successive feeding increased the probability of WT and Wolbachia transinfected mosquitoes surviving the EIP. When we estimated the odds of surviving the EIP for mosquitoes with Wolbachia relative to WT mosquitoes, successive feeding increased the chances of WT mosquitoes surviving the EIP more than in mosquitoes with Wolbachia, indicating a strong inhibitory effect of Wolbachia even in the context of natural frequent blood feeding behavior. Our work shows that mosquito feeding behavior should be considered when assessing the inhibitory effects of Wolbachia on DENV.
Functional constraints of wtf killer meiotic drivers
34527Nidamangala Srinivasa A, Campbell S, Venkatesan S, et al., PLOS Genetics, 21. 2025-02-21 09:42:22.
Killer meiotic drivers are selfish DNA loci that sabotage the gametes that do not inherit them from a driver+/driver− heterozygote. These drivers often employ toxic proteins that target essential cellular functions to cause the destruction of driver− gametes. Identifying the mechanisms of drivers can expand our understanding of infertility and reveal novel insights about the cellular functions targeted by drivers. In this work, we explore the molecular mechanisms underlying the wtf family of killer meiotic drivers found in fission yeasts. Each wtf killer acts using a toxic Wtfpoison protein that can be neutralized by a corresponding Wtfantidote protein. The wtf genes are rapidly evolving and extremely diverse. Here we found that self-assembly of Wtfpoison proteins is broadly conserved and associated with toxicity across the gene family, despite minimal amino acid conservation. In addition, we found the toxicity of Wtfpoison assemblies can be modulated by protein tags designed to increase or decrease the extent of the Wtfpoison assembly, implicating assembly size in toxicity. We also identified a conserved, critical role for the specific co-assembly of the Wtfpoison and Wtfantidote proteins in promoting effective neutralization of Wtfpoison toxicity. Finally, we engineered wtf alleles that encode toxic Wtfpoison proteins that are not effectively neutralized by their corresponding Wtfantidote proteins. The possibility of such self-destructive alleles reveals functional constraints on wtf evolution and suggests similar alleles could be cryptic contributors to infertility in fission yeast populations. As rapidly evolving killer meiotic drivers are widespread in eukaryotes, analogous self-killing drive alleles could contribute to sporadic infertility in many lineages.
Small RNA-mediated suppression of sex chromosome meiotic conflicts during Drosophila male gametogenesis
34613Vedanayagam, J., Biochemical Society Transactions, 53:281-291. 2025-02-06 11:14:24.
Meiosis is an evolutionarily conserved process in eukaryotes that ensures equal segregation of alleles and chromosomes during reproduction. Although parity in allelic transmission is the norm, selfish genes such as meiotic drivers can violate Mendel’s first law of segregation. Sex chromosome drive is a form of meiotic drive that leads to unequal segregation of sex chromosomes, resulting in sex-ratio distortion and/or sterility in the offspring. Adverse fitness effects due to sex chromosome drive trigger the evolution of suppressors to restore Mendelian segregation. However, the molecular mechanisms by which suppressors emerge and counteract meiotic drive genes remain unclear. Recent studies from Drosophila have shed light on the critical roles of small RNA-mediated post-transcriptional silencing in mitigating sex chromosome meiotic conflicts. This review highlights the recruitment of two distinct small RNA pathways to combat intragenomic conflicts during male gametogenesis and seeks to reveal the impact of molecular arms races between meiotic drivers and their suppressors in shaping genome and sex chromosome evolution.
Public attitudes to genetic technology for invasive pest control and preferences for engagement and information: a segmentation analysis
34499Hobman E.V., Mankad A., Carter, L., Collins K., Frontiers in Bioengineering and Biotechnology, 12. 2025-02-04 19:37:26.
Advances in genetic technology hold promise in managing the increasing problem of invasive pests. The current study sought to improve our understanding of public perceptions, and potential public engagement pathways and information needs as the technology is researched and potentially developed for deployment. A survey of 1,149 Australians was conducted, and the sample was segmented into 4 groups based on their attitudes: Certain Objectors, Fence Sitters, Cautious Supporters, and Certain Supporters. ‘Light touch’ engagement activities appeared to satisfy most people; yet more intensive engagements could be appropriate for a small group who hold negative views towards the technology. Across the board, people wanted to know about the potential risks, and the regulation and controls surrounding the gene editing technology. Those who held more positive views also showed an interest in the scientific processes and techniques, while people who held more negative views wanted to know what was being done to deal with social and ethical issues. The results provide insight into 1) the diversity of views, and associated beliefs and feelings, among the public when confronted with a synthetic biology solution to an environmental problem, 2) how public engagement activities can be tailored to align with people’s engagement beliefs and stated preferences, and 3) what issues biotechnology developers should address as they endeavour to design genetic technology in a socially responsible way.
Suppression of Aedes aegypti may not affect sympatric Aedes albopictus populations: findings from two years of entomological surveillance in Singapore
34497Wong, W.J., Tan, C.H., Verkaik, M.G. et al., Scientific Reports, 15:2253. 2025-02-04 19:28:45.
Globally, multiple trials have successfully demonstrated the effectiveness of novel tools, such as the sterile and incompatible insect techniques, in suppressing Aedes aegypti populations. However, there is concern that Aedes albopictus, another arbovirus-competent vector, may occupy the niches vacated by Ae. aegypti in areas where these species occur in sympatry. Here we investigate these concerns within the context of a Wolbachia-based Ae. aegypti suppression programme in highly urban Singapore, where general mosquito management is sustained through environmental management. Using nationally representative and longitudinal Aedes surveillance data, we show (1) no consistent association of increase in Ae. albopictus abundance with Ae. aegypti population suppression within Wolbachia-Aedes release sites, and (2) no significant change in the vertical spatial distribution of Ae. albopictus in high-rise residential apartment blocks even after two years of Ae. aegypti suppression. Finally, we report that dengue viruses were less prevalent in field Ae. albopictus than in Ae. aegypti, which is consistent with previous findings that Ae. albopictus is a lesser vector than Ae. aegypti in Singapore. Together, these results indicate that suppression of Ae. aegypti in the community may not be directly associated with any increase of Ae. albopictus population or capacity. Nonetheless, the risk of increase in Ae. albopictus population is anticipated if the reduction in disease transmission leads to less aggressive source reduction efforts and environmental management for mosquito control.
Controlling the frequency dynamics of homing gene drives for intermediate outcomes
34494Camm B., Fournier-Level A., G3: Genes|Genomes|Genetics, 2025-02-04 17:53:42.
Gene drives have enormous potential for solving biological issues by forcing the spread of desired alleles through populations. However, to safeguard from the potentially irreversible consequences on natural populations, gene drives with intermediate outcomes that neither fixate nor get removed from the population are of outstanding interest. To elucidate the conditions leading to intermediate gene drive outcomes, a stochastic, individual allele-focused gene drive model was developed to simulate the diffusion of a homing gene drive in a population. The frequencies of multiple alleles at a locus targeted by a gene drive were tracked under various scenarios. These explored the effect of gene drive conversion efficiency, strength and frequency of resistance alleles, dominance and strength of a fitness cost for the gene drive, and the level of inbreeding. Four outcomes were consistently observed: fixation, loss, temporary, and equilibrium. The latter 2 are defined by the frequency of the gene drive peaking then crashing or plateauing, respectively. No single variable determined the outcome of a drive. The difference between the conversion efficiency and resistance level, modeled quantitatively, differentiated the temporary and equilibrium outcomes. The frequency dynamics of the gene drive within outcomes varied extensively, with different variables driving these dynamics between outcomes. These simulation results highlight the possibility of fine-tuning gene drive outcomes and frequency dynamics. To that end, we provide a web application implementing our model, which will guide the safer design of gene drives able to achieve a range of controllable outcomes tailored to population management needs.
Generating sterile Anopheles mosquitoes to combat malaria transmission
34492Xu, X. and Champer, J., Research Communities by Springer Nature, 2025-02-04 17:49:08.
Malaria remains a deadly disease, claiming hundreds of thousands of lives worldwide every year. The primary vectors of malaria are Anopheles mosquitoes, including Anopheles gambiae and Anopheles stephensi. Controlling mosquito populations is crucial for stopping malaria transmission. Gene drive technology represents a promising alternative to traditional chemical-based control methods, offering a species-specific and eco-friendly approach. However, key challenges in developing gene drives include resistance formation due to end-joining repair after Cas9/gRNA cleavage and the fitness costs associated with drive heterozygotes. One of the most successful gene drive designs to date targets the doublesex (dsx) gene in Anopheles gambiae, as reported by Kyrou et al. (2018). The dsx gene plays a crucial role in sex differentiation, with distinct isoforms expressed in males and females. Disrupting the female-specific isoform results in female sterility. Ideally, only homozygous females exhibit sterility due to a male-like intersex phenotype, while male homozygous and heterozygous mosquitoes of both sexes remain fertile. This makes it a suitable target for a suppression gene drive aimed at reducing the number of fertile females and ultimately eliminating the population.
Establishment of pupal color as a screening marker and activity analysis of six U6 promoters in Zeugodacus cucurbitae using the white pupae gene
34487Fan Z., Wu Y., Zha X., Ma S., et al., Pest Management Science, 2025-02-04 17:36:39.
The genetic control method, which is environmentally friendly and species-specific, has effectively reduced or eliminated pests in many areas. One essential requirement to control a species is the identification of its genetic and molecular elements. Such elements, however, are rarely available in Zeugodacus cucurbitae, a very destructive insect pest worldwide. In this study, we knocked out the white pupae (wp) gene in Z. cucurbitae and generated a wp(−) strain, which has a white pupae phenotype. The white puparium color was successfully restored to brown by inserting the wp gene rescue allele into the genome of the wp(−) strain using piggyBac transgenic technology. The potential wp promoter was then truncated to drive the expression of the wp gene and the puparium color was rescued even by the 605 bp sequence upstream of its transcription initiation site. Further fertility tests showed that knocking out or rescuing the wp gene had no effect on the reproduction of adult flies. In addition, we identified six U6 promoters and tested their promoter activities in the embryos of Z. cucurbitae. The ZcU6-2 and ZcU6-1 promoters exhibited significantly higher activity than the others and are suitable for use in CRISPR technology-based genetic control methods. Our work first shows the success of applying piggyBac transgenic technology in Z. cucurbitae. Our results demonstrate a highly efficient transgenic screening marker by puparium color and the promoter activity of multiple ZcU6 promoters, facilitating the construction of transgenic strains that are used for genetic control of tephritid species. © 2025 Society of Chemical Industry.
Upscaling irradiation protocols of Aedes albopictus pupae within an SIT program in Reunion Island
34437Lucie Marquereau, Hanano Yamada, David Damiens, Antonin Leclercq, Brice Derepas, Cécile Brengues , Brice William Dain , Quentin Lejarre 1, Mickael Proudhon , Jeremy Bouyer and Louis Clément Gouagna, Scientific Reports, 14:12117. 2025-02-03 07:03:06.
The implementation of the sterile insect technique against Aedes albopictus relies on many parameters, in particular on the success of the sterilization of males to be released into the target area in overflooding numbers to mate with wild females. Achieving consistent sterility levels requires efficient and standardized irradiation protocols. Here, we assessed the effects of exposure environment, density of pupae, irradiation dose, quantity of water and location in the canister on the induced sterility of male pupae. We found that the irradiation of 2000 pupae in 130 ml of water and with a dose of 40 Gy was the best combination of factors to reliably sterilize male pupae with the specific irradiator used in our control program, allowing the sterilization of 14000 pupae per exposure cycle. The location in the canister had no effect on induced sterility. The results reported here allowed the standardization and optimization of irradiation protocols for a Sterile Insect Technique program to control Ae. albopictus on Reunion Island, which required the production of more than 300,000 sterile males per week.
Life-history traits of a fluorescent Anopheles arabiensis genetic sexing strain introgressed into South African genomic background
34435Nonhlanhla L. Ntoyi, Thabo Mashatola, Jérémy Bouyer, Carina Kraupa, Hamidou Maiga, Wadaka Mamai, Nanwintoum, Bimbile‑Somda, Thomas Wallner, Danilo O. Carvalho, Givemore Munhenga and Hanano Yamada, Malaria Journal, 21. 2025-02-03 06:44:24.
South Africa has set a mandate to eliminate local malaria transmission by 2023. In pursuit of this objective a Sterile Insect Technique programme targeting the main vector Anopheles arabiensis is currently under development. Significant progress has been made towards operationalizing the technology. However, one of the main limitations being faced is the absence of an efficient genetic sexing system. This study is an assessment of an An. arabiensis (AY‑2) strain carrying the full Y chromosome from Anopheles gambiae, including a transgenic red fluorescent marker, being introgressed into a South African genetic background as a potential tool for a reliable sexing system. Adult, virgin males from the An. arabiensis AY‑2 strain were outcrossed to virgin females from the South African, Kwazulu‑Natal An. arabiensis (KWAG strain) over three generations. Anopheles arabiensis AY‑2 fluorescent males were sorted as first instar larvae (L1) using the Complex Object Parametric Analyzer and Sorter (COPAS) and later screened as pupae to verify the sex. Life history traits of the novel hybrid KWAG‑AY2 strain were compared to the original fluorescent AY‑2 strain, the South African wild‑type KWAG strain and a standard laboratory An. arabiensis (Dongola reference strain). Results: The genetic stability of the sex‑linked fluorescent marker and the integrity and high level of sexing efficiency of the system were confirmed. No recombination events in respect to the fluorescent marker were detected over three rounds of introgression crosses. KWAG‑AY2 had higher hatch rates and survival of L1 to pupae and L1 to adult than the founding strains. AY‑2 showed faster development time of immature stages and larger adult body size, but lower larval survival rates. Adult KWAG males had significantly higher survival rates. There was no significant difference between the strains in fecundity and proportion of males. KWAG‑AY2 males performed better than reference strains in f light ability tests. The life history traits of KWAG‑AY2, its rearing efficiency under laboratory conditions, the preservation of the sex‑linked fluorescence and perfect sexing efficiency after three rounds of introgression crosses, indicate that it has potential for mass rearing. The potential risks and benefits associated to the use of this strain within the Sterile Insect Technique programme in South Africa are discussed.
Animal trypanosomosis eliminated in a major livestock production region in Senegal following the eradication of a tsetse population
34426Momar Talla Seck, Assane Guèye Fall, Adji Marème Gaye, Geoffrey Gimonneau, Mamadou Ciss, Mame Thierno Bakhoum, Baba Sall, Mireille Djimangali Bassène1, Renaud Lancelot, Marc J.B., Vreysen, and Jérémy Bouyer, Parasite 31, 31. 2025-02-03 04:43:45.
African animal trypanosomosis (AAT) was one of the main disease-related constraints to the development of intensive livestock production systems in the Niayes region of Senegal, a 30 km wide strip of land along the coast between Dakar and Saint-Louis. To overcome this constraint, the Government of Senegal initiated an area-wide integrated pest management programme combining chemical control tactics with the sterile insect technique to eradicate a population of the tsetse fly Glossina palpalis gambiensis Vanderplank, 1949 (Diptera, Glossinidae) in this area. The project was implemented following a phased conditional approach, and the target area was divided into three blocks treated sequentially. This study aims to assess the temporal dynamics of the prevalence of Trypanosoma spp. during the implementation of this programme. Between 2009 and 2022, 4,359 blood samples were collected from cattle and screened for trypanosomes using both the buffy coat and ELISA techniques, and PCR tests since 2020. The seroprevalence decreased from 18.9% (95%CI: 11.2–26.5) in 2009 to 0% in 2017–2022 in block 1, and from 92.9% (95%CI: 88.2–97) in 2010 to 0% in 2021 in block 2. The parasitological and serological data confirm the entomological monitoring results, i.e., that there is a high probability that the population of G. p. gambiensis has been eradicated from the Niayes and that the transmission of AAT has been interrupted in the treated area. These results indicate the effectiveness of the adopted approach and show that AAT can be sustainably removed through the creation of a zone free of G. p. gambiensis.
Integrating malaria vaccine and CRISPR/Cas9 gene drive: a comprehensive strategy for accelerated malaria eradication
34374Abraham, I.C., Aboje, J.E., Ukoaka, B.M. et al., Malaria Journal, 24. 2025-01-28 15:04:09.
Malaria remains a significant public health challenge, particularly in low- and middle-income countries, despite ongoing efforts to eradicate the disease. Recent advancements, including the rollout of malaria vaccines, such as RTS,S/AS01 and R21/Matrix-M™, offer new avenues for prevention. However, the rise of resistance to anti-malarial medications necessitates innovative strategies. This review explores the potential integration of CRISPR/Cas9 gene drive technology with malaria vaccination efforts to enhance vector control and reduce transmission. By employing gene drive mechanisms for population suppression and replacement of malaria-transmitting Anopheles mosquitoes, combined with the immunogenic properties of vaccines, a synergistic approach can be established. This paper discussed the need for integrated strategies to address the biological complexities of malaria and socio-economic factors influencing its prevalence. Challenges such as regulatory hurdles, community acceptance, ecological impacts, and sustainable funding are examined, alongside strategies for implementation within existing malaria control programmes. This integrated approach could significantly contribute to achieving the World Health Organization's targets for malaria reduction by 2030, ultimately enhancing public health outcomes and supporting broader socio-economic development.
Gene drive-based population suppression in the malaria vector Anopheles stephensi
34372Xu, X., Chen, J., Wang, Y. et al., Nature Communications, 16:1007. 2025-01-28 14:41:08.
Gene drives are alleles that can bias the inheritance of specific traits in target populations for the purpose of modification or suppression. Here, we construct a homing suppression drive in the major urban malaria vector Anopheles stephensi targeting the female-specific exon of doublesex, incorporating two gRNAs and a nanos-Cas9 to reduce functional resistance and improve female heterozygote fitness. Our results show that the drive was recessive sterile in both females and males, with various intersex phenotypes in drive homozygotes. Both male and female drive heterozygotes show only moderate drive conversion, indicating that the nanos promoter has lower activity in A. stephensi than in Anopheles gambiae. By amplicon sequencing, we detect a very low level of resistance allele formation. Combination of the homing suppression drive and a vasa-Cas9 line boosts the drive conversion rate of the homing drive to 100%, suggesting the use of similar systems for population suppression in a continuous release strategy with a lower release rate than SIT or fsRIDL techniques. This study contributes valuable insights to the development of more efficient and environmentally friendly pest control tools aimed at disrupting disease transmission.
Assessing Radiation-Induced Enzyme Activation in Aedes aegypti: Potential Challenges for SIT-Based Vector Management
34370Edvane Borges da Silva, Sloana Giesta Lemos Florêncio, Ademir Amaral, et al., Acta Tropica, 261. 2025-01-28 14:35:08.
This study characterizes the Aedes aegypti population from Fernando de Noronha Island, Pernambuco, Brazil, prior to implementing the Sterile Insect Technique (SIT). The main objective was to assess changes in glutathione S-transferase (GST) enzyme activity, previously linked to cypermethrin resistance in this population, in 2010. GST activity was measured in both male and female mosquitoes, mass-produced in the lab, after exposure to ionizing radiation. The population evaluation after six years showed complete susceptibility to cypermethrin, deltamethrin, and lambda-cyhalothrin, although GST activity remained altered, increasing further following irradiation (50% higher in irradiated males and 31% higher in irradiated females compared to non-irradiated controls). This stress response to gamma radiation suggests implications for the effectiveness and viability of sterile males, particularly when SIT is combined with chemical insecticides. These findings enhance our understanding of radiation's impact on metabolic responses of the sterile males and provide valuable insights for refining integrated control strategies in vector management programs.
A comprehensive review of biological and genetic control approaches for leishmaniasis vector sand flies; emphasis towards promoting tools for integrated vector management
34611Kumari, Y., Gunathilaka, N., Amarasinghe, D., PLOS Neglected Tropical Diseases, 19. 2025-01-27 11:07:43.
Leishmaniasis is a health problem in many regions with poor health and poor life resources. According to the World Health Organization (WHO), an estimated 700,000–1 million new cases arise annually. Effective control of sand fly vector populations is crucial for reducing the transmission of this disease. Therefore, this review aims to comprehensively examine and evaluate the current methods for controlling sand fly populations, focusing on biological and gene drive techniques. A detailed, comprehensive literature search was carried out using databases including Google Scholar, PubMed, ScienceDirect, and the National Library of Medicine (NIH). These searches were done using specific keywords related to the field of study. This current review identified several promising methods, including genetically modified sand flies, using transgenic approaches by taking advanced gene editing tools like Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas9) and genetic modification of symbiotic microorganisms for controlling sand fly populations, which appeared to be proven under laboratory and field settings. Genetic control approaches have many benefits over chemical control, including long-lasting effects on targets, high specificity, and less environmental impact. Advances in genetic engineering technologies, particularly CRISPR/Cas9, sterile insect techniques, and gene drive insect modification, offer new avenues for precise and efficient sand fly management. Future research should prioritize optimizing rearing and sterilization techniques, conducting controlled field trials, and fostering collaboration across disciplines to realize the potential of genetic control strategies in combating leishmaniasis.
Assessment of drive efficiency and resistance allele formation of a homing gene drive in the mosquito Aedes aegypti
34261Yang, X., Xu, X., Chen, Y. et al., Journal of Pest Science, 2025-01-14 09:57:33.
Aedes aegypti, known for transmitting viruses such as dengue, Zika and yellow fever, poses a significant public health threat. Conventional insecticides give rise to a range of issues, including ecological contamination and insect resistance. Hence, there is a pressing demand for environmentally-friendly, safer and more efficacious strategies for mosquito control. With the rapid advancement of the CRISPR/Cas9 system in gene function exploration and pest population control, substantial progress has been achieved in utilizing CRISPR/Cas9-based gene drive systems across various mosquito species. Only a few studies on gene drive technology have been conducted in Ae. aegypti. In this study, we constructed two complete drives for Ae. aegypti with different Cas9 promoters, each targeting kmo. Our drive based on PubCas9 had limited activity, but one with ExuCas9 exhibited super-Mendelian inheritance rates of approximately 60%. We observed low but detectable somatic activity of the drive and no evidence of maternally deposited Cas9. Germline resistance allele formation rates were similar to drive conversion rates, but most wild-type alleles in the germline remained uncut. Injections into the ExuCas9 drive line had 100% knockout efficiency among surviving offspring at three separate target genes. These results support the development and application of novel genetic pest control technologies aimed at combating Ae. aegypti.
Identification of novel genes responsible for a pollen killer present in local natural populations of Arabidopsis thaliana
34259Ricou, A., Simon, M., Duflos, R., et al, PLOS Genetics, 21. 2025-01-14 09:53:12.
Gamete killers are genetic loci that distort segregation in the progeny of hybrids because the killer allele promotes the elimination of the gametes that carry the sensitive allele. They are widely distributed in eukaryotes and are important for understanding genome evolution and speciation. We had previously identified a pollen killer in hybrids between two distant natural accessions of Arabidopsis thaliana. This pollen killer involves three genetically linked genes, and we previously reported the identification of the gene encoding the antidote that protects pollen grains from the killer activity. In this study, we identified the two other genes of the pollen killer by using CRISPR-Cas9 induced mutants. These two genes are necessary for the killer activity that we demonstrated to be specific to pollen. The cellular localization of the pollen killer encoded proteins suggests that the pollen killer activity involves the mitochondria. Sequence analyses reveal predicted domains from the same families in the killer proteins. In addition, the C-terminal half of one of the killer proteins is identical to the antidote, and one amino acid, crucial for the antidote activity, is also essential for the killer function. Investigating more than 700 worldwide accessions of A. thaliana, we confirmed that the locus is subject to important structural rearrangements and copy number variation. By exploiting available de novo genomic sequences, we propose a scenario for the emergence of this pollen killer in A. thaliana. Furthermore, we report the co-occurrence and behavior of killer and sensitive genotypes in several local populations, a prerequisite for studying gamete killer evolution in the wild. This highlights the potential of the Arabidopsis model not only for functional studies of gamete killers but also for investigating their evolutionary trajectories at complementary geographical scales.
Escalation of genome defense capacity enables control of an expanding meiotic driver
34251P. Chen, K.C. Pan, E.H. Park, et al., Proceedings of the National Academy of Sciences, 122. 2025-01-13 15:02:27.
From RNA interference to chromatin silencing, diverse genome defense pathways silence selfish genetic elements to safeguard genome integrity. Despite their diversity, different defense pathways share a modular organization, where numerous specificity factors identify diverse targets and common effectors silence them. In the PIWI-interacting RNA (piRNA) pathway, target RNAs are first identified by complementary base pairing with piRNAs and then silenced by PIWI-clade nucleases. Such a binary architecture allows the defense systems to be readily adaptable, where new targets can be captured via innovation of specificity factors. Thus, our current understanding of genome defense against lineage-specific selfish genes has been largely limited to specificity factor innovations, while it remains poorly understood whether other types of innovations are required. Here, we describe a new type of innovation, which escalates the genome defense capacity to control a recently expanded selfish gene in Drosophila melanogaster. Through a targeted RNAi screen for repressors of Stellate—a recently evolved meiotic driver—we identified a defense factor, Trailblazer. Trailblazer is a transcription factor that promotes the expression of two PIWI-clade nucleases, Aub and AGO3, to match Stellate in abundance. Recent innovation in the DNA-binding domain of Trailblazer enabled it to elevate Aub and AGO3 expression, thereby escalating the silencing capacity of piRNA pathway to tame expanded Stellate and safeguard fertility. As copy-number expansion is a recurrent feature of diverse selfish genes across the tree of life, we envision that augmenting the defense capacity to quantitatively match selfish genes is a repeatedly employed defense strategy in evolution.
Wolbachia-Based Approaches to Controlling Mosquito-Borne Viral Threats: Innovations, AI Integration, and Future Directions in the Context of Climate Change
34249Branda, F., Cella, E., Scarpa, F., et al., Viruses, 16:1868. 2025-01-13 14:55:50.
Wolbachia-based mosquito control strategies have gained significant attention as a sustainable approach to reduce the transmission of vector-borne diseases such as dengue, Zika, and chikungunya. These endosymbiotic bacteria can limit the ability of mosquitoes to transmit pathogens, offering a promising alternative to traditional chemical-based interventions. With the growing impact of climate change on mosquito population dynamics and disease transmission, Wolbachia interventions represent an adaptable and resilient strategy for mitigating the public health burden of vector-borne diseases. Changes in temperature, humidity, and rainfall patterns can alter mosquito breeding habitats and extend the geographical range of disease vectors, increasing the urgency for effective control measures. This review highlights innovations in Wolbachia-based mosquito control and explores future directions in the context of climate change. It emphasizes the integration of Wolbachia with other biological approaches and the need for multidisciplinary efforts to address climate-amplified disease risks. As ecosystems shift, Wolbachia interventions could be crucial in reducing mosquito-borne diseases, especially in vulnerable regions. AI integration in Wolbachia research presents opportunities to enhance mosquito control strategies by modeling ecological data, predicting mosquito dynamics, and optimizing intervention outcomes. Key areas include refining release strategies, real-time monitoring, and scaling interventions. Future opportunities lie in advancing AI-driven approaches for integrating Wolbachia with other vector control measures, promoting adaptive, data-driven responses to climate-amplified disease transmission.
Recommendations for Implementing Innovative Technologies to Control Aedes aegypti: Population Suppression Using a Combination of the Incompatible and Sterile Insect Techniques (IIT-SIT), Based on the Mexican Experience/Initiative
34247Martín-Park, A., Contreras-Perera, Y., et al., Insects, 15:987. 2025-01-13 11:41:22.
The future of Aedes aegypti control emphasizes the transition from traditional insecticides toward more sustainable and multisectoral integrated strategies, like using Wolbachia-carrying mosquitoes for population suppression or replacement. We reviewed the integration of the successful Mexican initiative, “Mosquitos Buenos”, with the key challenges outlined in the PAHO guidelines for incorporating innovative approaches into vector control programs. These challenges include establishing essential infrastructure, training personnel, managing field operations, and fostering community support. Our experience provides critical evidence to support the strategic National Plan for implementing and integrating IIT-SIT technologies to control Ae. aegypti and dengue. Furthermore, this experience serves as a foundation for other countries in the region interested in adopting these technologies. It underscores the importance of strategic planning, multisectoral collaboration, continuous evaluation, and scaling up innovative tools to ensure their long-term effectiveness and sustainability in urban areas where Aedes vectors and the diseases they transmit are endemic.
Mechanisms, Machinery, and Dynamics of Chromosome Segregation in Zea mays
34244Duffy, Marissa E., Michael Ngaw, Shayna E. Polsky, et al., Genes, 15. 2025-01-12 21:25:37.
Zea mays (maize) is both an agronomically important crop and a powerful genetic model system with an extensive molecular toolkit and genomic resources. With these tools, maize is an optimal system for cytogenetic study, particularly in the investigation of chromosome segregation. Here, we review the advances made in maize chromosome segregation, specifically in the regulation and dynamic assembly of the mitotic and meiotic spindle, the inheritance and mechanisms of the abnormal chromosome variant Ab10, the regulation of chromosome–spindle interactions via the spindle assembly checkpoint, and the function of kinetochore proteins that bridge chromosomes and spindles. In this review, we discuss these processes in a species-specific context including features that are both conserved and unique to Z. mays. Additionally, we highlight new protein structure prediction tools and make use of these tools to identify several novel kinetochore and spindle assembly checkpoint proteins in Z. mays.
A Y chromosome-linked genome editor for efficient population suppression in the malaria vector Anopheles gambiae
34215Tolosana, I., Willis, K., Gribble, M. et al., Nature Communications, 16:206. 2025-01-07 09:21:41.
Genetic control – the deliberate introduction of genetic traits to control a pest or vector population – offers a powerful tool to augment conventional mosquito control tools that have been successful in reducing malaria burden but that are compromised by a range of operational challenges. Self-sustaining genetic control strategies have shown great potential in laboratory settings, but hesitancy due to their invasive and persistent nature may delay their implementation. Here, instead, we describe a self-limiting strategy, designed to have geographically and temporally restricted effect, based on a Y chromosome-linked genome editor (YLE). The YLE comprises a CRISPR-Cas9 construct that is always inherited by males yet generates an autosomal dominant mutation that is transmitted to over 90% of the offspring and results in female-specific sterility. To our knowledge, our system represents a pioneering approach in the engineering of the Y chromosome to generate a genetic control strain for mosquitoes. Mathematical modelling shows that this YLE technology is up to seven times more efficient for population suppression than optimal versions of other self-limiting strategies, such as the widely used Sterile Insect Technique or the Release of Insects carrying a Dominant Lethal gene.
Wolbachia-based mosquito control: Environmental perspectives on population suppression and replacement strategies
34213Joydeb Bhattacharyya, Daniel L. Roelke, Acta Tropica, 262. 2025-01-07 09:07:50.
Mosquito-borne diseases pose a significant threat to global health, and traditional mosquito control methods often fall short of effectiveness. A promising alternative is the biological control strategy of transinfecting mosquitoes with Wolbachia, a bacterium capable of outcompeting harmful pathogens and reducing the ability of mosquitoes to transmit diseases. However, Wolbachia infections are sensitive to abiotic environmental factors such as temperature and humidity, which can affect their densities in mosquitoes and, consequently, their ability to block pathogens. This review evaluates the effectiveness of different Wolbachia strains transinfected into mosquitoes in reducing mosquito-borne diseases. It explores how Wolbachia contributes to mosquito population control and pathogen interference, highlighting the importance of mathematical models in understanding Wolbachia transmission dynamics. Additionally, the review addresses the potential impact on arboviral transmission and the challenges posed by environmental fluctuations in mosquito control programs.
Meiotic Drive and Speciation
34057Jeremy B. Searle and Fernando Pardo-Manuel de Villena, Annual Review of Genetics, 58:341-363. 2024-12-16 15:22:27.
Meiotic drive is the biased transmission of alleles from heterozygotes, contrary to Mendel's laws, and reflects intragenomic conflict rather than organism-level Darwinian selection. Theory has been developed as to how centromeric properties can promote female meiotic drive and how conflict between the X and Y chromosomes in males can promote male meiotic drive. There are empirical data that fit both the centromere drive and sex chromosome drive models. Sex chromosome drive may have relevance to speciation through the buildup of Dobzhansky-Muller incompatibilities involving drive and suppressor systems, studied particularly in Drosophila. Centromere drive may promote fixation of chromosomal rearrangements involving the centromere, and those fixed rearrangements may contribute to reproductive isolation, studied particularly in the house mouse. Genome-wide tests suggest that meiotic drive promotes allele fixation with regularity, and those studying the genomics of speciation need to be aware of the potential impact of such fixations on reproductive isolation. New species can originate in many different ways (including multiple factors acting together), and a substantial body of work on meiotic drive point to it being one of the processes involved.
Public attitudes to genetic technology for invasive pest control and preferences for engagement and information: A segmentation analysis
34055Elizabeth Virginia Hobman, Aditi Mankad, Lucy Carter, Kerry Collins, Frontiers in Bioengineering and Biotechnology, 12. 2024-12-16 14:49:47.
This research focusses on understanding (1) how people perceive genetic technology to control invasive animal pests (feral pigs, cats etc.), and (2) how people would like to be engaged on, and/or informed about, decisions regarding the development of this genetic technology. The results have direct relevance to biotechnology developers as they seek to better understand public likely response to genetic technology. Results revealed the presence of distinct segments where people varied systematically in their attitudes towards the technology, and their engagement beliefs and preferences, and information needs. The results provide practical direction on (1) how to design public engagement activities and science communications that accord with people's preferences, and (2) the issues that biotechnology developers should address as they endeavour to create socially responsible genetic technologies.
Biased social chromosome transmission in males of the fire ant Solenopsis invicta
34049Daniel R Hettesheimer, Haolin Zeng, Brendan G Hunt, Kenneth G Ross, G3: Genes|Genomes|Genetics, 2024-12-16 14:21:28.
Selfish genetic elements subvert the normal rules of inheritance to unfairly propagate themselves, often at the expense of other genomic elements and the fitness of individuals carrying them. Social life provides diverse avenues for the propagation of such elements. In the fire ant Solenopsis invicta, polymorphic social organization is controlled by a social chromosome, one variant of which (Sb) enhances its own transmission in polygyne colonies through effects on caste development and queen acceptance by workers. Whether the selfish effects of Sb extend to haploid (reproductive) males in this system is less clear. Here, we demonstrate a strong overrepresentation of the Sb social chromosome haplotype in reproductive males, relative to Mendelian expectations, in both the pupal and adult stages. We tested for the presence of selective execution of adult SB males by workers but did not detect such behavior. Combined with the presence of a strong imbalance in the haplotype frequencies already early in the pupal stage, these results indicate that the Sb supergene may distort male haplotype frequencies during larval or embryonic development. These findings are significant because they demonstrate yet another mode by which the selfish tendencies of the Sb supergene are manifested, illuminate complex interactions between Sb and the fire ant breeding system, inform the development of models of the population dynamics of Sb, and illustrate how a selfish supergene can increase in frequency in a population despite harboring deleterious mutations.
Assessing the Efficacy of Gene-Drive Technology in Reducing Malaria Transmission in Sub-Saharan Africa: Current Progress and Future Prospects
33876Bizimana Rukundo T., IAA Journal of Applied Sciences, 12(1):1-5. 2024-12-10 16:43:06.
Malaria continues to pose a significant public health challenge in Sub-Saharan Africa, necessitating innovative solutions to combat its transmission. This review examined the efficacy of gene-drive technology as a novel approach to reducing malaria transmission through genetic modifications of Anopheles mosquitoes. Utilizing a comprehensive literature review and analysis of experimental studies and pilot projects, we assessed the mechanisms of gene drives, including population suppression and replacement strategies. The findings indicated that gene-drive technology has the potential to significantly alter mosquito populations, thereby diminishing the burden of malaria. However, challenges such as ecological concerns, regulatory complexities, and public acceptance must be addressed for successful implementation. The integration of gene drives with existing malaria control measures, collaborative research efforts, and robust ethical governance is crucial for maximizing effectiveness and ensuring sustainable outcomes. Furthermore, monitoring and evaluation systems are essential for assessing the safety and efficacy of gene-drive initiatives. This review underscored the transformative potential of gene-drive technology in malaria prevention, advocating for continued dialogue among stakeholders to navigate the complexities associated with its application in Sub-Saharan Africa.
A meiotic driver hijacks an epigenetic reader to disrupt mitosis in noncarrier offspring
33620Yu Hua, Jianxiu Zhang, et al., PNAS, 121. 2024-11-12 14:39:25.
Killer meiotic drivers (KMDs) are selfish genetic elements that distort Mendelian inheritance by selectively killing meiotic products lacking the KMD element, thereby promoting their own propagation. Although KMDs have been found in diverse eukaryotes, only a limited number of them have been characterized at the molecular level, and their killing mechanisms remain largely unknown. In this study, we identify that a gene previously deemed essential for cell survival in the fission yeast Schizosaccharomyces pombe is a single-gene KMD. This gene, tdk1, kills nearly all tdk1Δ progeny in a tdk1+ × tdk1Δ cross. By analyzing polymorphisms of tdk1 among natural strains, we identify a resistant haplotype, HT3. This haplotype lacks killing ability yet confers resistance to killing by the wild-type tdk1. Proximity labeling experiments reveal an interaction between Tdk1, the protein product of tdk1, and the epigenetic reader Bdf1. Interestingly, the nonkilling Tdk1-HT3 variant does not interact with Bdf1. Cryoelectron microscopy further elucidated the binding interface between Tdk1 and Bdf1, pinpointing mutations within Tdk1-HT3 that disrupt this interface. During sexual reproduction, Tdk1 forms stable Bdf1-binding nuclear foci in all spores after meiosis. These foci persist in germinated tdk1Δ progeny and impede chromosome segregation during mitosis by generating aberrant chromosomal adhesions. This study identifies a KMD that masquerades as an essential gene and reveals the molecular mechanism by which this KMD hijacks cellular machinery to execute killing. Additionally, we unveil that losing the hijacking ability is an evolutionary path for this single-gene KMD to evolve into a nonkilling resistant haplotype.
Structural duality enables a single protein to act as a toxin–antidote pair for meiotic drive
33617Yu Hua, Jianxiu Zhang, et al., PNAS, 121. 2024-11-12 14:30:22.
In sexual reproduction, selfish genetic elements known as killer meiotic drivers (KMDs) bias inheritance by eliminating gametes that do not carry them. The selective killing behavior of most KMDs can be explained by a toxin–antidote model, where a toxin harms all gametes while an antidote provides resistance to the toxin in carriers. This study investigates whether and how the KMD element tdk1 in the fission yeast Schizosaccharomyces pombe deploys this strategy. Intriguingly, tdk1 relies on a single protein product, Tdk1, for both killing and resistance. We show that Tdk1 exists in a nontoxic tetrameric form during vegetative growth and meiosis but transforms into a distinct toxic form in spores. This toxic form acquires the ability to interact with the histone reader Bdf1 and assembles into supramolecular foci that disrupt mitosis in noncarriers after spore germination. In contrast, Tdk1 synthesized during germination of carrier spores is nontoxic and acts as an antidote, dismantling the preformed toxic Tdk1 assemblies. Replacement of the N-terminal region of Tdk1 with a tetramer-forming peptide reveals its dual roles in imposing an autoinhibited tetrameric conformation and facilitating the assembly of supramolecular foci when autoinhibition is released. Moreover, we successfully reconstituted a functional KMD element by combining a construct that exclusively expresses Tdk1 during meiosis (“toxin-only”) with another construct that expresses Tdk1 specifically during germination (“antidote-only”). This work uncovers a remarkable example of a single protein employing structural duality to form a toxin–antidote pair, expanding our understanding of the mechanisms underlying toxin–antidote systems.
Exploring The Dynamics of Gene Drive Mosquitoes Within Wild Populations Using an Agent-Based Simulation
33614S. Wickramasooriya, I. Mahmood, et al., IEEE Xplore, 2024-11-12 13:33:12.
Gene drive technology is emerging as a potentially powerful tool in combating vector-borne diseases – notably malaria. This study introduces an agent-based model (ABM) focused on the deployment of genetically engineered mosquitoes with gene drive (GEM) in Príncipe Island, Republic of São Tomé and Príncipe, an island nation in the Gulf of Guinea, West Africa. Grounded in empirical data from laboratory and field studies, our model forecasts the dynamics of mosquito populations central to devising efficacious GEM release strategies. The core objective is to evaluate the time required for GEMs to constitute 90% of the mosquito population and to elucidate their dispersal throughout the island. This research is instrumental in understanding GEM potential in controlling malaria vectors.
The Meiotic Drive: Intragenomic Competition and Selection
33610I. A. Zakharov, Russian Journal of Genetics, 60:1311-1318. 2024-11-12 12:02:24.
The article considers the distribution and mechanisms of the meiotic drive as a phenomenon manifested in unequal transmission of gene alleles and/or homologous chromosomes into gametes during meiosis. The meiotic drive has been studied in the most detail in Drosophila, mice, corn, and ascomycete fungi of the genera Neurospora and Podospora. The consequence of the meiotic drive is a shift in the frequencies of alleles in the gene pool and the maintenance of nonadaptive traits in the population.
