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.
Exploratory conversations with biodiversity-oriented civil society groups on the potential applications of gene drive-modified mosquitoes for malaria control in Tanzania
35354Finda, M.F., Sambo, M., Malika, G. et al., Transgenic Res, 35. 2026-01-13 09:53:50.
Gene drive-modified mosquitoes (GDMMs) are gaining attention as sustainable tools to complement existing malaria control strategies. Their ability to self-propagate and spread through wild mosquito populations offers the promise of low-cost, long-lasting impact, but also raises ecological, ethical, and governance concerns. In this evolving debate, civil society organizations (CSOs) are pivotal actors in shaping dialogue, representing community concerns, and influencing policy decisions. This study examined the perspectives and recommendations of biodiversity-oriented CSOs on the governance, testing, and potential application of GDMMs for malaria control in Tanzania. An exploratory qualitative design was employed, involving eight in-depth interviews, one focus group discussion, and three large group discussions with representatives from ten biodiversity-focused CSOs in Tanzania. Participants were selected purposively based on prior involvement in national or regional dialogues related to biotechnology; and the discussions focused on concerns, uncertainties and needs associated with testing and potential use of GDMMs for malaria control, as well as the balance of prospective benefits against long-term environmental risks. Transcripts were analyzed thematically using NVivo 12 Plus. Participants expressed cautious support for research on GDMMs for malaria control but raised concerns about scientific uncertainty, limited local expertise, inadequate transparency, potential transboundary effects and technological dependency. They emphasized the importance of generating robust, context-specific evidence before considering any environmental releases of gene drives; and highlighted concerns over inadequate accountability, particularly the lack of clarity on who would assume responsibility if adverse outcomes arise. They also advocated for early, inclusive, transparent, and continuous engagement with both target communities and the broader public. Lastly, to ensure objective and impartial oversight, they recommended development of local expertise that is independent of technology developers and sponsors. The CSOs’ perspectives were diverse but broadly aligned with the precautionary principle, calling for preventive action amid uncertainty, clear accountability, and the pursuit of safer alternatives. Although many expressed serious reservations about gene drive mosquitoes, there was a shared recognition that research on the technology is necessary, provided it is conducted under controlled, transparent, and auditable conditions. Overall, these exploratory discussions underscored the need for: (i) balanced dialogue between advocates and skeptics, (ii) robust ethical and regulatory frameworks covering the full life cycle of the technology, (iii) sustained community and stakeholder engagement from the early stages of research and development, (iv) enhancements of in-country capacity, and (v) national sovereignty in decision-making regarding GDMMs. Demonstrating and effectively communicating these elements will be as critical as ensuring their existence.
Selfish chromosomes exploit a germline checkpoint to eliminate competing gametes
35349Ridges, J.T., Bladen, J., King, T.D. et al., Nature, 2026-01-10 09:51:42.
Spermatid individualization is a common stage of spermiogenic failure suggesting that a male germline checkpoint may act at this stage during sperm development in Drosophila. However, the molecular identity of such a male germline checkpoint has remained elusive. Here, we show that Overdrive (Ovd), a gene dispensable for male fertility, is required for the selective elimination of post-meiotic spermatids targeted by selfish chromosomes. Gamete elimination occurs during the individualization stage of spermiogenesis, following histone-to-protamine transition failure of targeted spermatids. We show that Ovd is necessary for the selfish behavior of segregation distorters across distantly related Drosophila species, indicating that independent selfish chromosomes use common mechanisms. Our study suggests that the normal function of an Ovd-mediated germline checkpoint involves the elimination of abnormal gametes during male germline development, which is exploited by selfish chromosomes into eliminating competing sperm.
Wolbachia for malaria control
35347Zhang, Xinmi et al., Trends in Parasitology, 2026-01-08 10:34:56.
Malaria remains a major public health concern, and traditional vector control methods face growing challenges, underscoring the need for novel strategies. The success of Wolbachia-based dengue control, together with the establishment of Plasmodium-blocking Wolbachia transinfections in Anopheles, highlights the potential of a new tool for malaria control. This review discusses the main experimental systems for studying Wolbachia–Anopheles interactions, emphasizing the challenges of generating Wolbachia transinfected Anopheles gambiae strains. Experiments utilizing Plasmodium parasite challenge in transiently and stably infected Anopheles demonstrated that Wolbachia-induced Plasmodium suppression is feasible. Building on insights from Wolbachia–Aedes–arborvirus systems – and with current evidence from Anopheles systems – we also address mechanisms of Plasmodium suppression. Finally, we outline challenges and opportunities for translating these findings from proof-of-concept to field application.
Sterile insect technique reduces cabbage maggot (Diptera: Anthomyiidae) infestation in root crucifers in Canada
35337Anne-Marie Fortier, Allen Bush-Beaupré, Jade Savage, et al., Journal of Economic Entomology, 118:2710–2717. 2026-01-07 11:20:58.
The cabbage maggot (Delia radicum (L.)) is a major pest of brassica vegetables in Canada that has traditionally been managed with soil-applied insecticides. However, recent regulatory restrictions on key products such as chlorpyrifos have created a pressing need for alternative solutions. This study evaluates the sterile insect technique (SIT) as a control method for the cabbage maggot in root crucifers. Large-scale field trials conducted from 2019 to 2022 in Quebec (Canada) demonstrated significant reductions in D. radicum infestations in radish and daikon crops. Quality control measures confirmed the effectiveness of sterilization on cabbage maggot, with minimal impact on male performance. The results suggest that the SIT is a promising, environmentally friendly alternative to chemical control for cabbage maggot management. The study further highlights the importance of optimizing release strategies and improving predictive models to guide deployment. Overall, the SIT offers growers a viable option to reduce reliance on insecticides while maintaining crop health and yield.
Behavior modification in fruit flies through male annihilation technique: field applications, olfactory mechanisms, and future directions
35329Liu, Wei; Zhang, Sijia; Wang, Guirong, Entomologia Generalis, 45:1565 - 1576. 2026-01-06 14:51:47.
The male annihilation technique (MAT), as a method of insect behavior manipulation, is an environmentally friendly approach that has been successfully applied in over 150 fruit fly eradication programs worldwide. Despite their effectiveness in integrated pest management programs, concerns have long persisted about the safety of the primarily used male lures – particularly regarding the potential toxicity of methyl eugenol (ME). In this review, we propose a novel attractant screening and validation system for the future improvement of male lures, based on recent advancements in functional genomics and genetic manipulation technologies achieved in tephritid fruit flies. This system is built upon our knowledge of tephritid fruit flies’ core olfactory signal transduction pathway (“Male lures → Odorant receptors → Odorant receptor neurons → Glomerulus”). The working pipeline is centered around a transgenic Bactrocera strain with labeled male lure-responsive olfactory receptor neurons (ORNs) as the key targets. Electrophysiological responses and calcium activity serve as the readouts, while the decision criteria focus on increased intensity, stability, and specificity of neural activation induced by candidate compounds. This pipeline, compared to traditional behavior-first methods, enables the efficient screening of computationally identified candidate compounds and provides a foundation for evaluating their field stability and safety. More importantly, it represents a shift from empirical, field-based optimization to a molecularly guided, receptor-based design framework, advancing the development of enhanced male lure solutions for future applications in insect behavior manipulation.
Increasing the effective gene drive homing rate by targeting the haploinsufficient spermatogenesis gene KLHL10
35323Ceili L. Peng, W. Sebastian Kamau, Julien Freeman, et al., bioRxiv, 2026-01-05 12:04:02.
CRISPR-based gene drives represent a powerful new technology for limiting disease transmission and controlling invasive populations. These systems rely on homology-directed repair (HDR) to ‘drive’ a genetic element through a population. However, mammals tend to favor non-homologous end joining (NHEJ), which generates mutations that halt further drive propagation. Here, we describe the experimental characterization of a gene drive system targeting the haploinsufficient spermatogenesis gene KLHL10 in the laboratory mouse. Using a newly designed ‘coding sequence cassette’ we introduce downstream guide RNAs within the gene, ensuring that sperm undergoing NHEJ are selectively removed from the population. As a proof of principle, we demonstrate that targeting KLHL10 with constitutively expressed LbCas12a results in strong selection against frameshift-containing sperm, validating the core purification mechanism required for this drive strategy. Unexpectedly, we also observed that female offspring lacked most frameshift mutations, suggesting a previously unrecognized role for KLHL10 in oogenesis or early embryonic development.
From song to stories: assessing the impact of exposure to arts-based community engagement tools in shaping knowledge, attitudes, and acceptability toward the Sterile Insect Technique for malaria control in South Africa
35319Manana, P.N., Jewett, S. & Munhenga, G., Malaria Journal, 24. 2026-01-05 11:31:18.
Community engagement (CE) is essential for public health interventions. This is particularly important when introducing novel technologies, such as the Sterile Insect Technique (SIT), that require strong community understanding and acceptance. Against this background, arts-based CE strategies, including music, drama, and radio short stories, were developed and piloted, but their effectiveness remained unevaluated. This study assessed whether exposure to arts-based CE approaches influenced community knowledge, attitudes, and acceptance of the SIT in uMkhanyakude District, KwaZulu-Natal, South Africa. A cross-sectional survey to understand the influence of arts-based CE approaches was conducted in the Jozini municipality, uMkhanyakude District, after community exposure to these CE productions. Structured interviews were conducted with randomly sampled community members. Data were collected on CE exposure and SIT-related knowledge, attitudes, and acceptance. A chi-square test and a stepwise ordinal logistic regression were used to analyze the data after adjusting for sociodemographic factors. Among 614 participants, only 26.2% (n = 161) were exposed to arts-based CE approaches. Those exposed were more likely to correctly identify that female mosquitoes feed on blood as compared to the unexposed (95.0% vs. 85.8%, p = 0.008), and to express support for SIT (e.g., 98.1% vs. 89.4% agreed with upcoming releases, p = 0.003). Exposure remained a significant predictor of SIT acceptance in multivariate models (OR 0.65, 95% CI 0.45–0.94). Positive attitudes and accurate knowledge also independently predicted greater acceptance. Arts-based CE tools were effective in supporting the introduction of SIT by improving knowledge and acceptance. However, limited exposure suggests the need for more sustained and widely accessible engagement strategies to maximize reach and long-term impact. These findings suggest that artistic productions, especially when delivered through culturally relevant, multimodal formats, play a meaningful role in shaping community receptiveness to novel vector control methods like the SIT.
Monitoring the Capacity of Microsporidia MB Transgenerational Spread in Anopheles arabiensis Populations
35317Boanyah, G. Y., Koekemoer, L. L., Herren, J. K., & Bukhari, T., Insects, 16. 2026-01-05 11:06:39.
Microsporidia MB is a natural symbiont of Anopheles arabiensis Patton, 1905 that blocks Plasmodium transmission without compromising mosquito fitness. Developing this symbiont for malaria control requires a thorough understanding of its transmission dynamics across generations under environmentally relevant conditions. This study aimed to evaluate the transgenerational spread of Microsporidia MB in semi-field settings. From field-collected infected females (G0), several independent replicates of Microsporidia MB-infected An. arabiensis were established and maintained under semi-field conditions for six generations (F1–F6). All the mosquitoes were screened for Microsporidia MB prevalence and infection intensity using qPCR after death. Temperature and humidity and wing size were recorded. Two replicates sustained through F6. Microsporidia MB prevalence and intensity increased from F1 to F3–F4 before declining. A weak positive correlation was observed between prevalence and temperature, but not humidity. Female mosquitoes exhibited higher infection intensities. Female wing size varied across generations, while male size remained consistent. This first study on Microsporidia MB transgenerational transmission under semi-field conditions revealed a pattern of initial increase followed by decline in prevalence and intensity. The stability of male size supports the potential use of infected males in release programs. These findings underscore additional investigations into environmental drivers for mosquito symbiont prevalence.
Genetic Biocontrol Strategy Considerations for Mosquito Control in the Pacific Island Countries and Territories
35315Adam E. Vorsino, Tim Harvey-Samuel, Limb K. Hapairai, et al., Current Opinion in Insect Science, 2026-01-05 10:49:54.
Mosquito-borne diseases pose an existential threat to the health, economies, and unique ecosystems of Pacific Island Countries and Territories (PICTs). The remoteness of these islands, combined with the presence of highly competent mosquito vectors, complicates disease surveillance and vector control efforts. In response, the PICTs have become a focal point for the development and application of Genetic BioControl (GBC) technologies designed to break vector-borne disease transmission cycles. However, the application of GBC tools in this region warrants careful consideration of its unique history, including a legacy of colonialism, and challenges associated with logistic hurdles. Through meaningful community engagement and authentic collaborations, drawing from local knowledge, and building local capacity, the sustainable, efficient and effective deployment of GBC tools may be achieved.
Genetic Allee Effects for Controlling Invasive Populations
35313Louis Nowell Nicolle, Alex Fournier-Level, Charles Robin, et al., Molecular Ecology, 2026-01-02 10:37:23.
Invasive pests threaten food security and devastate ecosystems. A universal problem in their management is that small populations can easily evade detection. This makes identifying new incursions challenging and complicates efforts to eradicate or contain established populations. If newly founded populations exhibited a strong Allee effect, small populations would tend towards extinction and most new incursions would go extinct without the need for detection or intervention. Of course, invasive species rarely exhibit strong Allee effects, but new genetic technologies make it conceivable to impose one. Here we consider how introduction of genetic load can cause a genetic Allee effect that reduces the establishment probability of small founder populations. Using numerical and individual-based modelling, we examine the fate of populations sampled from a larger invasive source population carrying deleterious recessive alleles. Our analysis reveals that the genetic load unmasked by founding can dramatically reduce the establishment probability of small populations across a wide range of parameter space. A sterile mutation effect is more effective than a lethal mutation effect, but X-linkage offers minimal benefit over autosomal inheritance. Although extinction of newly founded populations is a common outcome, it may be challenging to achieve in species with very high reproductive outputs. Distributing deleterious recessive alleles across a large number of loci at low frequencies was more effective than distributing them across fewer loci at higher frequencies. Our findings suggest that driving deleterious recessives into a source population may render it less prone to establish in new areas.
The role of toxin/antidote genes in the maintenance and evolution of accessory chromosomes in Fusarium
35333Linnea Sandell, Adrian Forsythe, Anna Mirandola, et al., Genetics, 231. 2025-12-31 14:56:39.
The genomic diversity of many fungal species is augmented by accessory chromosomes, which are variably present in individual strains. These genomic regions evolve rapidly, accumulating genes important in pathogenicity but also harbor a significant number of transposable elements. This duality suggests a trade-off: accessory chromosomes provide infection-related benefits while otherwise being deleterious due to their highly repetitive nature and contributions to genomic instability. Despite this, accessory chromosomes often appear to be stably maintained even when strains are grown on media, with no plant host. Previously, we had observed that genes homologous to meiotic drive toxin/antidote proteins from Podospora anserina (Spoks) are abundant on accessory chromosomes in various Fusarium species. Using a functionality screen in yeast, we demonstrate that some of these homologs have active toxin and antidote properties. We propose that these selfish genes could maintain accessory chromosomes during vegetative growth and may influence their spread via parasexual cycles. Finally, as Spok genes are found on the newly described transposable element superfamily Starships, we also present a model for how these transposable elements could play a role in forming accessory chromosomes and regions. These results illuminate a mysterious facet of fungal biology, a key step towards describing the origin, spread, and maintenance of pathogenicity in many fungal species.
Evolutionary persistence and divergence of the tdk killer meiotic driver family
35476Fan-Yi Zhang, Guo-Song Jia, Jing-Yi Ren, et al., bioRxiv, 2025-12-29 18:22:02.
Killer meiotic drivers (KMDs) are selfish genetic elements that achieve super-Mendelian inheritance by selectively eliminating gametes lacking the driver. Although predicted to arise recurrently, KMDs are generally considered evolutionarily ephemeral—going extinct after fixation or host suppression. The identification of tdk1, a single-gene KMD in the fission yeast Schizosaccharomyces pombe, provides a model for studying KMD evolution. Here, we identify two divergent tdk1 homologs (tdk210 and tdk203) from S. cryophilus, a fission yeast species that diverged ∼100 million years ago from S. pombe, as active KMDs. These three KMDs all act via post-germination killing, disrupting chromosome segregation in noncarrier progeny. Notably, they also exhibit striking functional divergences: tdk1, tdk210, and tdk203 are mutually incompatible (showing no cross-resistance), and the latter two act independently of Bdf1/Bdf2—host chromatin proteins required for tdk1 killing. Phylogenetic analyses of the dozens of tdk family genes in Schizosaccharomyces support long-term persistence and rapid evolutionary dynamics of this gene family. Remarkably, homologs in distantly related fungal phyla display genomic and structural similarities to Schizosaccharomyces tdk genes, suggesting a deeply rooted origin of this KMD family in fungi. Our findings reveal that a single KMD family can undergo repeated functional innovation—generating mutually incompatible variants and rewiring host dependencies—while maintaining a conserved killing mode over deep evolutionary time.
Wolbachia as a transformative tool for mosquito-borne disease control: a comprehensive review of mechanisms, efficacy, and future directions
35325Minaei, M. E., Yousefi Nojookambari, N., Ghodraty, M., & Yazdansetad, S., Pathogens and Global Health, 2025-12-23 12:15:44.
Mosquito-borne infectious diseases such as dengue, Zika, chikungunya, and malaria continue to pose significant public health challenges worldwide. Traditional control methods, including the use of insecticides and environmental management, have shown limited effectiveness due to insecticide resistance and logistical challenges. Wolbachia-based strategies, which leverage the bacterium’s unique ability to manipulate mosquito reproduction and block pathogens, present a promising, albeit not universally applicable, method for reducing the transmission of mosquito-borne diseases. Field trials have demonstrated significant but variable efficacy. This systematic review synthesizes the latest findings on Wolbachia-based interventions, focusing on their mechanisms, efficacy, and potential for large-scale implementation. We conducted a comprehensive literature search across multiple databases, including PubMed, Scopus, and Web of Science, to identify relevant studies published between 1990 and 2025. Our review highlights the promising results of Wolbachia-based strategies in reducing mosquito populations and disease transmission, while also addressing the challenges and limitations of this approach. We conclude that Wolbachia-based strategies hold great potential for revolutionizing mosquito-borne disease control, but further research and careful consideration of ecological and ethical implications are necessary for their successful implementation.
Analysis of a household-scale model for the invasion of Wolbachia into a resident mosquito population
35327Barlow, A., Penington, S. & Adams, B., Journal of Mathematical Biology, 92. 2025-12-22 12:18:25.
In areas infested with Aedes aegypti mosquitoes it may be possible to control dengue, and some other vector-borne diseases, by introducing Wolbachia-infected mosquitoes into the wildtype population. Thus far, empirical and theoretical studies of Wolbachia release have tended to focus on the dynamics at the community scale. However, Ae. aegypti mosquitoes typically dwell in and around the same houses as the people they bite and it can be insightful to explore what happens at the household scale where small population sizes lead to inherently stochastic dynamics. Here we use a continuous-time Markov framework to develop a stochastic household model for small populations of wildtype and Wolbachia-infected mosquitoes. We investigate the transient and long term dynamics of the system, in particular examining the impact of stochasticity on the Wolbachia invasion threshold and bistability between the wildtype-only and Wolbachia-only steady states previously observed in deterministic models. We focus on the influence of key parameters which determine the fitness cost of Wolbachia infection and the probability of Wolbachia vertical transmission. Using Markov and matrix population theory, we derive salient characteristics of the system including the probability of successful Wolbachia invasion, the expected time until invasion and the probability that a Wolbachia-infected population reverts to a wildtype population. These attributes can inform strategies for the release of Wolbachia-infected mosquitoes. In addition, we find that releasing the minimum number of Wolbachia-infected mosquitoes required to displace a resident wildtype population according to the deterministic model, only results in that outcome about 20% of the time in the stochastic model; a significantly larger release is required to reach a steady state composed entirely of Wolbachia-infected mosquitoes 90% of the time.
A target product profile for a rapid diagnostic test to monitor mosquito gene drive presence and frequency
35345Prateek Verma, Sebald Verkuijl, Calvin K. Yee, et al., bioRxiv, 2025-12-18 10:23:36.
Malaria remains a major global health challenge, with over 263 million cases and nearly 600,000 deaths reported in 2023, the majority in sub-Saharan Africa. While conventional interventions such as insecticide-treated nets, indoor residual spraying and antimalarial drugs have reduced transmission, progress has stalled due to the limitations of these interventions and the emergence of resistance. Gene drive-modified mosquitoes represent a promising, potentially transformative vector control strategy, capable of spreading malaria-refractory traits or suppressing mosquito populations. Successful field deployment will depend upon monitoring systems to track the presence and frequency of gene drive constructs as they spread and persist. Current molecular surveillance techniques, though effective, are resource-intensive and reliant on laboratory infrastructure and technical competencies. Here, we make the case for a near-universal and low-cost rapid diagnostic test (RDT) designed to detect gene drive mosquitoes in the field, to complement existing surveillance infrastructure. Two use cases are outlined: i) to detect the presence of the drive construct in a new population, and ii) to provide an estimate of drive frequency prior to more accurate laboratory-based measurements. We provide a target product profile for the RDT outlining minimally essential and ideal characteristics, including test procedures, sensitivity, specificity, usability by a range of stakeholders in field settings, and compatibility with pooled testing of mosquito samples. An RDT for gene drive construct detection would support community access and participation in monitoring, enhance regulatory oversight, and promote transparency in field trials, thereby facilitating responsible deployment of gene drive-based malaria interventions.
Strategies to improve the efficiency of homing gene drives with multiplexed gRNAs
35416Chen, W., Wu, P. & Champer, J., BMC Biol, 24. 2025-12-12 16:50:27.
CRISPR homing gene drive holds great potential for pest control, but its success is challenged by the generation of resistance alleles through end-joining repair. Using multiple gRNAs to target adjacent sites within a conserved gene can prevent functional resistance by allowing repeated cleavage events, but poor homology during DNA repair may compromise efficiency. We first assessed the efficiency of single gRNA drives with truncated homology arms in Drosophila melanogaster mimicking a multiplexed system in which only one site is cleaved. Integrating results into a detailed gRNA multiplexing model, we found that efficiency loss was greater than expected. To mitigate this, we evaluated two new strategies: (1) extended homology arms to span all target sites (with mutations in the PAMs to prevent self-cleavage) and (2) a population-level gRNA multiplexing system involving two or more drives, each carrying two gRNAs. Extended homology arms did not result in notable improvement in conversion efficiency, and the extended region could be lost during drive conversion. The population-level multiplexing gRNAs strategy was more promising, though the intentionally mutated PAM also could not be consistently inherited. Simulations of homing suppression drives applying population-level multiplexed gRNAs increased the success rate of population elimination and reduced the time required for suppression. Future drive designs requiring a larger number of gRNAs could potentially be improved. The design relying on extended homology arms may not represent an optimal strategy. However, population-level multiplexing gRNAs could serve as a promising alternative, enhancing efficiency while maintaining tolerance to functional resistance.
Improving Wolbachia-based control programs in urban settings: Insights from spatial modeling
35335Florez D, Cortez R, Hyman JM, Qu Z, PLoS Neglected Tropical Diseases, 19. 2025-12-12 11:08:20.
Arboviral diseases remain a major public health concern, particularly in tropical and subtropical regions where mosquito populations thrive. One promising strategy to curb transmission is the release of Aedes aegypti mosquitoes infected with Wolbachia, a bacterium that reduces their ability to spread viruses. However, past large-scale releases have not always been successful, especially in complex urban settings, where restricted access to certain areas often leads to infection establishment failures and wasted resources. To address this, we developed a spatial model that simulates how Wolbachia-infected mosquitoes are established in different urban environments. We also explored strategies to improve their success under constraints on release size and the efficacy level of insecticide used for pre-release interventions. Our findings suggest that targeted releases are most effective in areas with limited mosquito movement without additional insecticide use. In higher-dispersal areas, reducing at least 35% of wild mosquitoes before release significantly improves establishment within nine months. Additionally, distributing releases over 2-5 weekly batches enhances success more than a single large release, even without other interventions. These findings offer practical insights for designing cost-effective and efficient Wolbachia-based mosquito control programs, reducing the burden of mosquito-borne diseases on vulnerable communities.
Homing gene drive strains for genetic suppression of agricultural insect pests
35331Yadav, Amarish K.; Tarrand, Ariel E.; Scott, Maxwell J., Entomologia Generalis, 45:1577 - 1590. 2025-12-04 14:52:03.
Agricultural insect pests cause substantial losses in crop productivity each year. Genetic-based strategies provide economical and environmentally friendly ways to limit pests that reproduce sexually. In contrast to conventional genetic methods (e.g. SIT), homing gene drives (HGDs) are potentially capable of suppressing or modifying an entire pest population in a short period of time after releasing a small number of HGD insects. The advent of CRISPR/Cas gene editing tools has simplified the engineering of gene drives, and the progress made on HGDs in various insects in the recent past is encouraging. However, to date HGDs have been developed and evaluated in only a few agricultural pest species. These drives have been designed to suppress populations by targeting genes essential for female development or fertility. Homing gene drive relies on homology directed repair (HDR) of the Cas9-mediated double-stranded DNA break in germ cells. Consequently, the use of other DNA repair pathways such as non-homologous end joining (NHEJ) and micro-homology mediated end joining (MMEJ) can retard homing. Further, establishment of functional resistant alleles through these end-joining pathways is one of the major challenges associated with HGDs. Development of HGDs in some pest species is challenging due to the technical difficulties of making transgenics. Identification and characterization of germline-specific promoters and other regulatory elements to achieve precise HDR (in early meiosis) can facilitate efficient homing. In this review, we highlight the recent progress made towards developing HGDs in agricultural insect pests with insights gained from studies in model organisms (e.g. Drosophila melanogaster).
A temperature-sensitive CRISPR-Cas12a system for sterile insect technique
35361Nguyen, C., Omotayo, A.I., Sanz Juste, S. et al., Nature Communications, 16. 2025-11-14 11:49:30.
The sterile insect technique (SIT) reduces population numbers by releasing sterile males that produce non-viable progeny. Specifically, CRISPR/Cas9-based precision-guided SIT (pgSIT) generates sterile males through genetic crosses of two transgenic lines: a Cas9 strain and a guide RNA (gRNA) strain targeting male sterility and female viability or infertility. However, pgSIT requires separate maintenance of the two lines and sorting to obtain sterile males, creating possible challenges for scaling. To overcome this, we propose using Cas12a nuclease, which is inoperative at lower temperatures but active at higher temperatures. Here, we develop a Cas12a-based pgSIT system involving a single strain containing both the Cas12a nuclease and gRNAs to induce male sterility and female lethality. This strain can be maintained as a mixed stock of both sexes and only activated by increasing temperature, producing sterile males after just one generation. By reducing the challenges that arise with maintaining two separate lines, this system could offer a scalable alternative for vector control in combating vector-borne diseases.
Variants in Cas9 and nanos regulatory elements modulate activity and reduce resistance allele formation in homing gene drive
35294Ruizhi Zhou, Jie Du, Nicky R. Faber, Jackson Champer, bioRxiv, 2025-11-09 18:15:12.
Gene drive is a novel approach for controlling vector borne disease via either population modification or suppression. Even with high efficiency, though, overall drive performance can be reduced by somatic Cas9 expression and by maternal deposition of Cas9, leading to resistance allele formation. The nanos promoter for Cas9 shows very little leaky somatic expression, but it causes high rates of embryo resistance allele formation in Drosophila melanogaster. By truncating the promoter, we reduced rates of embryo resistance to undetectable levels, but germline cutting in females decreased by over half. Germline cutting and successful drive conversion was eventually lost when only the 5′ UTR was present, though males still retained moderate germline drive efficiency. Several additional methods were tested to improve performance, including additional suppressor elements to the 3′ UTR and introns to increase expression level. The most successful of these was the addition of a second nuclear localization signal, which substantially increased activity when coupled with a full-length or truncated nanos promoter. Overall, these experiments show the potential to modulate Cas9 regulatory elements to achieve desired expression for gene drive applications, while also showcasing the difficulty of obtaining an optimal activity profile.
Inhibiting invasive fish reproduction via germ cell xenotransplantation and hybrid lethality
35292Amano, Y., Baba, H., Kishi, D. et al., Scientific Reports, 15. 2025-11-09 17:56:43.
Invasive alien fish constitute a major problem in the conservation of aquatic ecosystems. The most common method of exterminating invasive fish is physical capture by fishing gear; however, it is extremely difficult to eradicate them. Here, we developed a novel methodology to inhibit the reproduction of invasive fish by releasing surrogate males of the same species, which produce sperm of different species, into rivers, allowing them to produce lethal hybrids through natural spawning. This study focused on rainbow trout, an invasive fish that negatively impacts ecosystems worldwide. Since rainbow trout × brown trout hybrids are lethal, surrogate rainbow trout producing brown trout sperm were created by germline stem cell transplantation. Releasing the surrogate males into an experimental river inhabited by wild-type rainbow trout females revealed that they naturally mated and produced lethal hybrid offspring. This is a novel and powerful methodology for eradicating invasive fish.
Integrating mosquito genomics into simulation modeling: Opportunities for better-informed biocontrol
35282Gordana Rašić, John M. Marshall, Current Opinion in Insect Science, 2025-11-03 11:25:51.
Mosquito-borne diseases remain a major global health burden, and novel biocontrol tools are quickly advancing from the laboratory to the field. Mathematical models play a central role in evaluating these interventions, yet their predictive accuracy depends on robust parameterization. Population genomics presents a powerful opportunity to address this challenge. Here, we review progress at the interface between mosquito genomics and biocontrol modeling, highlighting how genomic data have informed our understanding of mosquito population structure, standing genetic variation at gene drive target sites, and sources of resurgence for suppressed populations. We also discuss frontiers, including new approaches to quantifying gene flow, mating behaviors, and inbreeding depression, all of which shape intervention outcomes. By tapping this potential to better quantify our understanding of mosquito ecology, modelers can develop context-specific models with better predictive accuracy, supporting efficacy and risk assessment, design of field trials and interventions, and promotion of regulation and public trust.
Synthetic biology approaches to generate temperature-sensitive alleles for the Sterile Insect Technique
35280Chun Yin Leung, Ernst A. Wimmer, Hassan M. M. Ahmed, Insect Science, 2025-11-03 11:22:09.
The Sterile Insect Technique (SIT) is an environmentally friendly, sustainable pest control approach, which uses large-scale releases of sterile insects to suppress or eradicate target populations through infertile matings. The efficiency of SIT is enhanced by male-only releases requiring genetic sexing strains (GSSs) that are classically based on selectable recessive visible markers or temperature-sensitive lethal (tsl) mutations and a rescue by a wild-type allele translocated to the male-determining chromosome. The transfer of identified or designed temperature-sensitive alleles might allow the generation of neoclassical GSSs in additional SIT target species. By using precise genome-editing tools, such as CRISPR/Cas, the creation of specific mutations in target genes and the integration of a wild-type copy is feasible without the introduction of foreign DNA. This might ease regulation of neoclassical GSSs, since they are not considered transgenic. However, integration and expression of genes at male-determining loci or chromosomes is not reliably established. Therefore, additional strategies to link temperature-sensitive phenotypes to female development are required, which could be achieved by targeting genes involved in dosage compensation or sex determination. To create temperature-sensitive alleles, rational protein design using advanced modeling and prediction tools to evaluate and tailor the effect of mutations on protein stability and temperature sensitivity can be used. In addition, emerging synthetic biology strategies such as temperature-inducible N-degrons or temperature-sensitive inteins provide powerful tools to generate temperature sensitivity. Such approaches should enable conditional control over proteins causing female lethality or sex conversion and therefore promise straightforward generic approaches to generate GSSs for male-only production in SIT target species.
Effect of male age at the time of irradiation on the sexual performance of sterile Ceratitis capitata males: insights from remating female offspring
35278Edwin Mauricio Ramírez-Santos, Pedro Alfonso Rendón Arana, et al., Insect Science, 2025-11-03 11:19:51.
The Sterile Insect Technique (SIT) is an effective strategy for controlling insect pests, such as the Mediterranean fruit fly (Ceratitis capitata, Wiedemann). The effectiveness of the SIT depends on the ability of the sterile males to mate and their capacity to induce sterility in wild females. This study evaluated how the irradiation age affects their sexual performance, measured by the outcome of female remating events. Males of the GSS VIENNA 8D53− were irradiated at eleven different ages, from 72 h before emergence (pupal stage) to 72 h after emergence (adult stage) and mated with wild females. These females were subsequently allowed to mate with fertile males from the fluorescent TSS VIENNA 8 1260. The presence of fluorescent offspring was used as indicator of second-male paternity. Results showed that males irradiated at post-emergence ages produced the lowest egg-to-pupae conversion rate, indicating a greater ability to prevent females from producing offspring after remating with a fertile male. In contrast, males irradiated at pre-emergence ages were associated with higher numbers of fluorescent offspring. Although no significant differences were found in mating competitiveness (RSI), the outcome of the remating showed differences in the effectiveness of initial matings. These findings highlight the importance of considering the age of flies at time of irradiation in mass-rearing protocols to enhance the efficacy of SIT programs targeting C. capitata and suggest that irradiating males later in their life cycle, such as adult stages or in pupae close to adult emergence, limit offspring if females remate with fertile males in the field.
Suitability of a chilled environmental box of the Precision X-RAD 320 cabinet style irradiator for the irradiation of mosquitoes and tsetse in the context of the sterile insect technique
35276Hanano Yamada, Bénéwendé Aristide Kaboré, Samar Eisa, et al., Journal of Economic Entomology, 2025-11-03 11:17:02.
A cabinet-style small animal X-irradiator outfitted with an environmental chamber which can provide a consistent, chilled environment during irradiation was tested to sterilize the human and animal disease vectors Aedes aegypti Linnaeus (Diptera: Culicidae), Anopheles arabiensis Patton (Diptera: Culicidae), Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) in the frame of the sterile insect technique (SIT). The environmental chamber enables the irradiation of immobilized, compacted adult insects avoiding mechanical damage incurred by movement and, thereby, maintaining better insect quality. For the species tested, there was no significant difference in dose response when irradiating late-stage pupae or adults, and chilling at 7 °C did not affect irradiation outcome in terms of sterility induced. The X-irradiator was shown to be effective and suitable for the sterilization of these important target species of the SIT and offers a practical means to sterilize insects at the adult stage which require chilling for immobilization.
Impact of long-term mass-rearing on the genetic structure of tsetse fly Glossina palpalis gambiensis colonies
35273Kiswend-sida M. Dera, Soumaïla Pagabeleguem, Tito Tresor Melachio Tanekou, et al., Insect Science, 32. 2025-11-02 17:49:38.
Tsetse flies are the sole cyclic vectors of African trypanosomes, which cause human and animal African trypanosomiases in Africa. Tsetse fly control remains a promising option for disease management. The sterile insect technique (SIT) stands as an environmentally friendly tool to control tsetse populations. SIT requires the mass-rearing of competent sterile males to mate with wild females. However, long-term colonization might affect the genetic structure of the reared flies. This study investigated the genetic structure of four Glossina palpalis gambiensis colonies of different ages: two originating from Senegal (SEN and ICIRSEN) and two from Burkina Faso (CIR and IBD). Samples from these colonies were genotyped at ten microsatellite loci, followed by downstream population genetic analyses. The results show that the two colonies from Burkina Faso collected from close sites (∼20 km apart) over 45-year interval retained the same genetic background (FST_CIR∼IBD ≈ 0, P-value = 0.47). These flies were however, genetically different from those from the Senegal colonies (FST_CIR∼SEN ≈ 0.047; FST_IBD∼SEN ≈ 0.058, P-value = 10−4). Moreover, no significant difference was detected in the gene diversity of the CIR and IBD colonies, with HS values of 0.650 and 0.665, respectively. The inbreeding coefficient showed that all four colonies where under Hardy–Weinberg equilibrium, with FIS values of 0.026, 0.012, −0.064, and 0.001, for CIR, IBD, ICIRSEN, and SEN, respectively. Furthermore, no sign of a recent bottleneck was identified in tsetse samples from any of the four colonies. The results suggest that long-term mass-rearing of tsetse flies has no significant impact on their genetic background and diversity.
The nanosd integral gene drive enables population modification of the malaria vector Anopheles gambiae
35269Pei-Shi Yen, Sebald A N R Verkuijl, Paolo Capriotti, et al., G3 Genes|Genomes|Genetics, 2025-11-02 17:38:52.
The modification of mosquito populations at scale through CRISPR-Cas9-mediated homing gene drives is a promising route for malaria vector control. Integral gene drives (IGDs) are designed to utilise the regulatory sequences of endogenous genes to reduce the size of the modification required for nuclease and effector expression. In this study, we describe the creation and characterisation of the nanosd IGD, which targets and is inserted into the nanos gene of the malaria vector Anopheles gambiae, and show that it achieves high rates of gene drive (98.4% in females, 99.5% in males). We find that homozygous nanosd females but not males show impaired fecundity and exhibit variable degrees of ovary underdevelopment. Transcriptomic analysis of ovaries points to decreased transcript levels of the nanos gene when harbouring Cas9 and changes to other fertility-related genes. As a minimal genetic modification, nanosd does not induce widespread transcriptomic perturbations that would affect vector competence, and we show that its susceptibility to Plasmodium spp. and O’nyong nyong virus infection remains similar to wild-type mosquitoes. Importantly, we find that nanosd propagates efficiently in caged mosquito populations and is maintained as a source of Cas9 after the emergence of drive-resistant alleles, whilst also mobilising a non-autonomous antiparasitic effector modification. The nanosd gene drive shows promise as a genetic tool for malaria vector control via population modification, and we outline steps towards its further optimisation.
SIT-ia: A Software-Hardware System to Improve Male Sorting Efficacy for the Sterile Insect Technique
35267de la Vega, G., Smith, L., Soria-Mercier, L., et al., Insects, 16. 2025-11-02 17:34:18.
This research addresses a challenge in using the Sterile Insect Technique (SIT), an eco-friendly pest control method. For SIT to work, only sterile male insects can be released, but sorting males from females by hand is slow and laborious. The study introduces a new automated system called SIT-ia that uses artificial intelligence (AI) to quickly and accurately tell male and female flies apart. When tested on the spotted-wing drosophila (Drosophila suzukii), the system was 98.6% accurate. A key benefit is its speed: SIT-ia can sort 1000 flies in about 70 min, which is 40 min faster than human experts. This innovation makes sex-sorting a more efficient and practical process, needed for managing pest insects in a sustainable way. Invasive insects can cause significant economic impacts to agriculture worldwide and impact human health. Traditional pest management methods that include chemical insecticides have raised increasing environmental and health concerns, prompting the need for sustainable alternatives. The Sterile Insect Technique (SIT), which consists of releasing sterile males of a target pest to mate with wild females, is held as a promising solution. However, the success of SIT relies on the release of sterile males. The efficient separation of sexes prior to sterilization and release is necessary. This study presents SIT-ia, a software–hardware system that utilizes artificial intelligence (AI) and computer vision to automate the sex-sorting process. We showcase its use with the fruit fly pest D. suzukii. The system was able to identify males from females with a 98.6% accuracy, sorting 1000 sterile flies in ~70 min, which is nearly half the time involved in manual sorting by experts (i.e., ~112 min). This simple device can easily be adopted in SIT production protocols, improving the feasibility and efficacy of improved pest management practices.
Highlight: Self-limiting gene drive suppresses malaria mosquitoes
35263Gorm Palmgren, CRISPR Medicine News, 2025-11-02 17:22:29.
Malaria claimed over 600,000 lives in 2022, with Anopheles gambiae serving as one of the most efficient vectors in sub-Saharan Africa, where approximately 96% of malaria deaths occur. The emergence of insecticide resistance threatens progress in disease control, prompting the development of genetic strategies to address it. CRISPR-homing gene drives have emerged as the most studied self-sustaining approaches, whilst various self-limiting methods that require repeated releases continue to be explored. The research team developed a system, termed Male-Drive Female-Sterile (MDFS), that exploits CRISPR-Cas9 to simultaneously perform two distinct functions (see Figure 1). The genetic construct contains an eCFP fluorescent marker, a Cas9 endonuclease under the control of the germline vasa2 promoter, and a guide RNA targeting the female-specific exon 5 of the doublesex gene. The construct was integrated into the doublesex locus at the intron 4–exon 5 boundary using recombinase-mediated cassette exchange.
A male-drive female-sterile system for the self-limited control of the malaria mosquito Anopheles gambiae
35261Strampelli, A., Willis, K., Gulliford, H.R. et al., Nature Communications, 16. 2025-10-28 08:43:17.
Despite great leaps forward in preventing and treating malaria, several challenges, including insecticide resistance, have hindered progress in fighting the disease. Thus, there is a pressing need for new tools to control malaria, including the use of genetically modified mosquitoes (GMMs) in the field. Various genetic strategies for vector control are currently explored, ranging from self-sustaining GMMs with unrestricted geographic and temporal spread to self-limiting alternatives. Here, we describe a self-limiting gene drive strategy called Male Drive Female Sterile (MDFS) targeting Anopheles gambiae, a major malaria vector. The MDFS genetic construct causes dominant sterility in females, while transgenic males remain fertile, allowing them to transmit the female sterility trait at super-Mendelian rates. Laboratory studies show that repeated releases of MDFS can lead to elimination of caged mosquito populations. Based on these findings, modelling suggests MDFS could be a highly effective and self-limiting strategy for suppressing wild malaria mosquito populations.
Developing Y chromosome sex ratio distorters in the model insect Drosophila melanogaster
35259Yael Arien, Chen Zacharia, Elad Yonah, et al., bioRxiv, 2025-10-28 08:24:56.
CRISPR-Cas9 sex ratio distortion (SRD) systems can suppress insect populations by biasing progeny toward males, but realizing such systems requires reliable Cas9 expression from insect Y chromosomes. Here, we tested whether the spermatocyte-specific betaTub85D promoter can drive functional Cas9 expression when inserted on the Drosophila melanogaster Y chromosome. Using CRISPR-mediated homology-directed repair, we generated a Y-linked betaTub85D-Cas9-T2A-eGFP construct and compared its activity with an autosomal counterpart. Whereas autosomal betaTub85D-Cas9 induced strong male-biased sex ratios when paired with an X-poisoning gRNA, the Y-linked construct failed to distort sex ratios and exhibited approximately 2,000-fold reduction in Cas9 transcript abundance. Nonetheless, weak but detectable GFP fluorescence and Cas9 transcripts confirmed partial Y-linked promoter activity. These findings provide the first direct experimental evidence of meiotic sex chromosome inactivation (MSCI) acting on the Drosophila Y chromosome, revealing that meiotic promoters can remain weakly active despite strong repression. This work defines transcriptional limits of the Drosophila Y chromosome and informs the design of next-generation Y-linked gene drives for sustainable insect control.
Successful suppression of Aedes aegypti (Diptera: Culicidae) with the sterile insect technique also results in larger female mosquitoes
35257Katherine G Evans, Rachel Morreale, Steven Stenhouse, et al., Journal of Medical Entomology, 2025-10-27 11:04:27.
Sterile insect technique (SIT) is an effective method for controlling pests and has been increasing in popularity to control Aedes mosquitoes. SIT involves inundating an area with sterilized male mosquitoes to reduce egg hatch by reducing the number of fertile matings and ultimately the number of wild adults. Enacting mortality early in the larval life of Aedes mosquitoes can result in counter-productive effects due to reduced competition among developing larvae. SIT projects targeting mosquitoes have historically assessed effectiveness by monitoring egg or adult numbers, leaving out crucial information on what occurs at the larval stage. Our experiments involved collecting and hatching eggs from ovitraps in an SIT-treatment zone and 2 nearby non-SIT zones. We reared the resulting larvae in density and resource conditions similar to those in the field and compared numbers of emerging adults and sizes of emerging adult females from SIT and non-SIT zones. We hypothesize that the effectiveness of SIT in reducing adult populations is modified by density dependent mortality and density dependent growth among larvae. Our results indicate that SIT effectively suppressed the production of adult Aedes aegypti (L) in the SIT zone compared to non-SIT zones. Additionally, female Ae. aegypti, collected as eggs and reared in laboratory-simulated field conditions were significantly larger from the SIT zone than those from the non-SIT zones. Larger SIT-zone females are consistent with reduced intraspecific competition among larvae. Suppression of adult production in the SIT zone resulted in reduced predicted vectorial capacity, despite the increase in female size.
Intermittent releases: a modelling approach for sterile insect technique in mosquito control
35255Bhattacharyya, J., Banerjee, M. & Banerjee, S, Journal of Mathematical Biology, 91. 2025-10-27 10:49:16.
An unconventional and environmentally friendly mosquito management approach offers a sustainable solution that protects both the environment and human health. One such method is the Sterile Insect Technique (SIT), which holds promise as a mosquito control strategy by releasing sterilized male mosquitoes into the wild-type (WT) mosquito population. Since the success of SIT depends on the strategic planning of sterile mosquito releases, this paper examines a stage-structured model for mosquito populations with a density-dependent threshold for sterile male mosquito release, where releases occur only when the ratio of WT to sterile mosquito populations exceeds a critical threshold. Using intermittent releases, the proposed SIT model is designed to optimally align the release of sterile male mosquitoes with WT and sterile mosquito population densities, maintaining WT mosquito suppression at a predefined threshold and offering a more effective alternative to continuous release strategies. We employ Filippov’s modelling approach to investigate how intermittent releases, represented by piecewise-smooth functions, affect the dynamics of the system, particularly when mosquito populations exceed the predefined threshold. To explore the dynamical complexities, we employ Filippov’s convex method by defining the vector field in the discontinuous region as convex combinations of adjacent fields, allowing for the analysis of sliding motion and the identification of discontinuity-induced bifurcations through differential inclusions. Our findings identify the minimum release rate of sterile mosquitoes required to achieve the desired suppression level, highlighting the need to increase this rate due to increased WT mosquito immigration, reduced survival and mating fitness of sterile mosquitoes, and limitations in mosquito surveillance accuracy.
Selection, counterselection, and conditional gene expression for genetic biocontrol of insects
35249Melanie Hempel, Zhijian Tu, Insect Science, 2025-10-16 09:29:04.
Genetic biocontrol methods are species-specific ways to suppress or modify pest insect populations to mitigate their economic or health impact. Successful genetic biocontrol often requires mass releases of only males of the target species. Reliable and cost-effective sex separation is a major bottleneck to the implementation of genetic biocontrol of many important species of agricultural and medical importance. Conditional selection is critical to resolving this major challenge. A diverse array of tools, such as the temperature-sensitive systems, the Gal4/UAS, QF/QUAS, and Tet-on/off bipartite systems, and the photoactivatable systems, have been established in various insect species. In this review, we focus on how various means of conditional expression have been used to achieve sex separation. We also describe other means of selection and counterselection to achieve sex separation without conditional gene expression. By providing examples across many species and discussing the strengths and weaknesses of each method, we hope to facilitate the design and application of conditional systems to improve genetic biocontrol of insect pests.
Pervasive suppressors halt the spread of selfish Segregation Distorter in a natural population
35247Ching-Ho Chang, Tyler Handler, Nick Fuda, et al., bioRxiv, 2025-10-16 09:21:01.
Meiotic drivers are selfish genetic elements that subvert Mendelian inheritance to increase their own transmission, yet they are typically found at low frequencies across natural populations. The factors that limit their spread remain unclear. To investigate this paradox, we studied the Segregation Distorter (SD) system, a selfish coadapted gene complex in Drosophila melanogaster. SD biases its transmission by killing sperm carrying a homologous chromosome bearing a target locus, Responder (Rsp), which appear as satellite repeats. Such selfish killing impairs male fertility and imposes selective pressure on the host genome to evolve resistance, either by deleting Rsp copies or acquiring unlinked suppressors. To characterize the spectrum of Rsp alleles and the frequency of segregating suppressors, we surveyed 90 strains from the Drosophila Genome Reference Panel. Rather than loss of Rsp, we found that over half of the strains (52/90) harbor suppressors located on the X chromosome or autosomes, but not the Y chromosome. The widespread presence of strong suppressors limited the resolution of our genome-wide association mapping; however, recombination analysis identified a strong X-linked suppressor to a ~300 kb interval on the chromosome. Together, our findings suggest that pervasive, multilocus suppression constrains the spread of SD in natural populations.
Exploring experts’ uncertainties about gene drive technology for agricultural pest control in the U.S.: a qualitative study to inform innovation and decision-making
35241Barry, N., Barnhill, S.K. & Johnson, B.B., Environment Systems and Decisions, 45. 2025-10-15 08:34:10.
As experts consider what it might look like for gene drives to manage agricultural pests, there remain several uncertainties across a broad range of issues, including technical, ecological, regulatory, and social implications. Drawing on 25 expert interviews, we parse out these uncertainties and the potential for Adaptive Management to help guide development, deployment, and governance of gene drives for invasive agricultural pest management. Adaptive Management emerged specifically to attend to uncertainties in complex social-ecological systems, prescribing collective learning and responsiveness to stakeholder feedback to effectively reach management goals. Thus, Adaptive Management provides clear direction on how to account for and make decisions in the face of considerable uncertainties surrounding these gene drive tools. We also give some attention to the ways in which the uncertainties that are specific to agricultural applications are somewhat distinct from or consistent with global discourse around gene drive development across sectors.
Requirements for designing cluster randomised control trials to detect suppression of malaria vector population densities
35239Hancock, P.A., Hui, TY.J., Epopa, P.S. et al., BMC Biology, 23. 2025-10-15 08:17:09.
Novel interventions for mosquito-borne disease control which release modified mosquitoes that are sterilised or genetically modified to cause offspring inviability are progressing towards field applications. Cluster randomised control trials (CRCTs) could provide robust assessment of intervention efficacy in suppressing mosquito populations in field environments, but guidance on designing CRCTs to detect mosquito suppression impacts is limited. We developed statistical models to simulate CRCTs, informed by a 5-year time series measuring densities of malaria vector species from the Anopheles gambiae complex in four villages in western Burkina Faso. We estimated requirements for parallel and step wedge designs, varying the targeted vector species, the suppression effect and the monitoring regime. For a suppression effect of 50%, 21–22 clusters were required to detect suppression with 90% power when all An. gambiae complex species were targeted, while 24–26 clusters were required when only An. coluzzii was targeted and 60–66 clusters were required when only An. gambiae was targeted. For stronger suppression effects, required trial sizes depended less on target species, with 9–10 clusters being sufficient to detect a 90% suppression effect. We investigated how reducing sampling effort, by sampling fewer houses and restricting sampling to rainy season months, affected statistical power. Our results provide empirically based guidance for designing CRCTs to evaluate interventions aiming to suppress malaria vector populations.
Engineering gene drive docking sites in a haplolethal locus in Anopheles gambiae
35231Smidler, A.L., Marrogi, E.A., Scott, S. et al., Scientific Reports, 15. 2025-10-09 10:19:39.
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 and functional r1 alleles permits the cell to survive. Here we outline the development and characterization of two ΦC31-Recombination mediated cassette exchange 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 putative 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 in the process reveal a major lethality and infertility 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 development of future gene drives designed to target haplolethal loci in anophelines and, potentially, other metazoans.
Finding the perfect promoter: Correlating single-cell transcriptome data with gene drive performance
35228Yingke Wu, Yunchen Xia, Ziyin Yao, et al., bioRxiv, 2025-10-09 10:07:12.
Gene drive can control pathogen transmission or suppress vector populations by spreading drive alleles with super-Mendelian inheritance. CRISPR homing drive currently represents the most powerful type, and regulating Cas9 expression with specific promoters has been effective for improving drive performance. However, selecting these is often a major challenge. Here, we evaluated 35 Cas9 constructs driven by distinct promoters in different gene drive systems and identified associations between drive performance and single-cell RNA expression patterns of the promoter-associated genes. Our results indicate that higher drive conversion is significantly associated with elevated expression of the promoter-associated gene in the respective reproductive cells, but embryo resistance allele formation correlates with excessive female germline expression. For males, early germline expression produces superior performance. Thus, we find that optimal drive performance requires restricting Cas9 expression to a tight quantitative and spatiotemporal window. In addition, found that in situ integrated rhino-Cas9 constructs significantly reduce somatic expression, underscoring the importance of genomic locus. On the basis of these results, we propose criteria for selecting promoters, providing a theoretical rationale and practical guidance for optimization of promoter elements in homing gene drive systems.
CRISPR/Cas9-germline editing of Biomphalaria glabrata: A breakthrough in genetic modification of snails that transmit schistosomiasis
35226Kouhei Oonuma et al., Science Advances, 11. 2025-10-09 10:03:53.
Human schistosomiasis remains one of the most devastating parasitic diseases worldwide, and the development of genetically modified vector snails has long been a goal in the field. Here, we report the successful creation of genetically modified Biomphalaria glabrata, an important intermediate host, using CRISPR/Cas9 gene editing. We targeted the fibrinogen-related protein 3.1 (FREP3.1) gene, confirmed stable germline transmission of the mutated gene, and established two different homozygous FREP3.1-edited lines. Disruption of the FREP 3.1 gene did not alter snail susceptibility to Schistosoma mansoni infection, possibly due to a limited role of FREP3.1 in resistance or to functional redundancy and/or compensatory expression within the highly diverse FREP gene family. Our study demonstrates successful germline editing, effective ex ovo culture of decapsulated embryos, and the generation of viable, genetically modified B. glabrata snails, thereby establishing a foundation for future genetic strategies to control schistosomiasis.
Systemic tumor-targeting gene drive vectors proactively eliminate drug resistance in solid tumors
35223Scott M Leighow, Michael Hemann, Justin Robert Pritchard, bioRxiv, 2025-10-07 13:57:44.
While targeted therapies have revolutionized cancer treatment, drug resistance remains a major barrier to their curative potential. We recently demonstrated biological proof-of-concept for selection gene drive circuits, a technology that overwrites disease evolution to proactively eliminate resistance in vivo, but translation requires a delivery method compatible with disseminated metastatic disease. Now, we demonstrate a clinically feasible delivery solution with novel tumor-targeting lentiviral vectors that selectively install these therapeutic circuits in tumor cells in situ. Systemic administration of these vectors demonstrated durable elimination of visible tumor burden and minimal body weight loss, validating the translational potential of a new class of genetic medicines for long-term control of resistance in cancer.
Bacteria-mediated dsRNA delivery for mosquito-borne virus control
35219Mine Altinli, Sean P. Leonard, Alain Kohl, et al., Trends in Parasitology, 41:880-893. 2025-10-05 14:37:07.
Mosquito-borne viruses represent an increasing global public health threat, exacerbated by urbanisation and climate change, thus making effective mosquito control essential. RNA interference (RNAi), a sequence-specific gene regulation mechanism, can be a flexible vector control tool. RNAi effectors, such as double-stranded RNA (dsRNA), can target mosquito genes or the viruses they carry, disrupting development or suppressing infection. However, current RNAi delivery methods are ineffective. Engineered bacterial symbionts offer a promising alternative for delivery, as they can produce dsRNA directly within mosquitoes. However, bacterial RNAi delivery in mosquitoes remains underexplored. We review emerging genetic tools, insights from RNAi and bacteria–mosquito interactions to outline priorities for realising bacterial RNAi as an efficient and sustainable vector control strategy.
Wolbachia-Based biocontrol of Aedes aegypti: Current Progress, Challenges, and future prospects
35217Ashif Ahamed, Safdar Ali, Mehboob Hoque, Journal of Invertebrate Pathology, 2025-10-05 13:03:30.
Wolbachia is used as potential bio-control tool to reduce the dengue mosquitoes and also to reduce dengue virus (DENV) load in transinfected Aedes aegypti. Different field trials including the ones by the World Mosquito Program (WMP) have deployed Wolbachia carrying DENV primary vectors at different target sites worldwide. Field trials suggest that through the Population Replacement Strategy (PRS) and Incompatible Insect Technique (IIT), Wolbachia can introgress into the local Ae. aegypti population or reduce the population size of the Aedes aegypti by cytoplasmic incompatibility phenomenon and subsequent reduction in dengue incidences at target sites. Challenges for this strategy are to establish and maintain the transinfected mosquito population, choosing the appropriate strain of the bacteria, long term establishment of transinfected dengue mosquitoes for several subsequent generations, selecting the appropriate approach of mosquito field release, operational challenges, and the viral evolution. Moreover, the outcome of Wolbachia mediated biological control of Aedes aegypti in a broad scale is yet to be seen and the long-term stability of Wolbachia in transinfected mosquitoes remains unconfirmed. Significant success has been recorded in a broad scale deployment of wAlbB-carrying Aedes aegypti through the ongoing Wolbachia Malaysia project, resulting in a reduction in dengue fever cases. Successful large-deployment of this strategy has also been performed in Colombia and Indonesia (1.7 to 3.3 million people and 135–540 km2 area). Similar investigations on broad scale for longer period across different environmental conditions using transinfected mosquito deployment and associated risk analysis are imperative before adopting this biological control approach as a potent dengue control strategy worldwide.
The Stellate meiotic drive system of Drosophila melanogaster is active in contemporary populations
35215Benjamin K McCormick, Daniel A Barbash, Andrew G Clark, bioRxiv, 2025-10-05 12:58:27.
Meiotic drivers are selfish elements that bias their own transmission so that they are overrepresented among the functional gametes produced. The selective costs imposed by drivers on their hosts may trigger intragenomic conflict, promoting the evolution of suppressors and fueling an ongoing arms race between drivers and suppressors. Stellate (Ste) is an X-linked tandemly arrayed multicopy gene. Its copy number ranges from 3 to more than 300 among Drosophila melanogaster strains from the Global Diversity Lines. In wild-type animals, Ste expression is usually suppressed by homologous piRNAs produced from the Suppressor of Stellate (Su(Ste)) array on the Y chromosome. Derepression of Ste in the absence Su(Ste) results in the formation of proteinaceous crystals in spermatocytes, chromatin compaction defects, reductions in fertility, and female-biased sex ratios arising from under-recovery of Y-bearing sperm. Despite extensive study, the function of the Stellate array and evolutionary significance of its persistence in the genome have remained elusive. It has been suggested to be a now-inactive relic of an ancient meiotic drive system, as perturbations in lab stocks can produce Ste-mediated meiotic distortions. Meiotic drive occurring among natural variants, however, has not been reported. We established crosses between females with high Ste copy number X chromosomes and males carrying low Su(Ste) copy number Y chromosomes and found that the male progeny displayed non-Mendelian sex chromosome transmission. Importantly, deletion of the euSte array in an otherwise matched genetic background rescues this phenotype, demonstrating that Stellate is an active driver in contemporary populations.
Impact of larval diet on fitness outcomes of Aedes aegypti mosquitoes infected with wAlbB and wMelM
35213Md Yatim, M.F., Ross, P.A., Gu, X. et al., Parasites Vectors, 18. 2025-10-02 15:06:04.
Releases of Wolbachia-infected Aedes aegypti are being used to effectively control diseases caused by arboviruses, such as dengue. A well-balanced larval diet is essential for producing Wolbachia-infected mosquitoes with optimal fitness for release. In this study, four diets with varying protein-to-carbohydrate ratios were tested with three Ae. aegypti lines (carrying the wAlbB, wMelM Wolbachia infections or uninfected) to identify optimal diets for larval rearing on the basis of diet allocations ranging from 0.4 to 3.2 mg/larva/day. The diets were selected on the basis of a review of existing literature and are characterized by progressively increasing protein and decreasing carbohydrate content: diet 1 (Pd) was based on plant-based protein (low protein and high carbohydrate), diet 2 (Kd) was based on animal-based protein (moderate protein and high carbohydrate), diet 3 (Fd) involved Hikari fish food (high protein and moderate carbohydrate), and diet 4 (IAEA) followed a widely used very-high-protein and low-carbohydrate diet developed by the International Atomic Energy Agency (IAEA). The optimal concentration for each diet was determined using a fitness index that incorporated pupation success, fecundity, hatch proportion and development time. The optimal dietary allocations for diets 1–4 were 1.6, 1.2, 1.2 and 0.8 mg/larva/day, respectively, regardless of Wolbachia status. There was a consistent significant positive relationship between female wing length and fecundity in wAlbB (r2 = 0.881), wMelM (r2 = 0.329), and uninfected (r2 = 0.886) mosquitoes. Diet 3 (Fd) at optimal food allocation reduced a fitness cost commonly associated with the wAlbB line compared with the uninfected line when provided at the optimal concentration. The wMelM line showed a persistently low fecundity regardless of diet and concentration. These findings highlight the importance of an appropriate larval diet and dietary allocations in optimizing mosquito fitness for Wolbachia-based vector control programs. Further research into dietary composition, gut microbial interactions and Wolbachia associations could refine larval nutrition strategies, enhancing the effectiveness of mass-rearing for release programs.
D. melanogaster meiotic driver Stellate compromises sperm development by impeding nuclear envelope remodeling
35211Xuefeng M Meng, Yukiko M Yamashita, bioRxiv, 2025-10-02 15:00:55.
Meiotic drive is a phenomenon that violates Mendels Law of Equal Segregation, leading to biased transmission of the meiotic driver to the offspring. D. melanogaster Stellate (Ste) is an X-linked meiotic driver that preferentially harms Y-chromosome-bearing spermatids, thereby favoring the transmission of the X chromosome to the next generation. We have recently shown that Ste protein segregates asymmetrically during meiosis I with a strong bias toward the Y-chromosome-inheriting side, leading to the eventual demise of the Y-chromosome-containing spermatids. However, the cellular mechanisms by which Ste protein interferes with spermatid development remain unknown. Here, we show that Ste-containing spermatids are delayed in the process of nuclear envelope remodeling, an essential process during sperm DNA compaction. We show that Lamin Dm0, a component of the nuclear lamina, is rapidly removed during nuclear envelope remodeling during the early stages of normal spermatid development. However, Ste-containing spermatid retained Lamin Dm0 for a prolonged time. Delayed Lamin Dm0 removal is associated with defective formation of the dense complex, which is composed of the bundle of microtubules and serves as a structural support for sperm nuclear morphogenesis. Defective dense complex formation in Ste-containing spermatid led to defective sperm DNA compaction. Together, the present study reveals an unexpected cellular mechanism by which a meiotic driver, Ste, sabotages sperm development.
Dispersal and survival of gamma-irradiated Culex quinquefasciatus: Implications for sterile insect technique applications
35207Nungki Hapsari Suryaningtyas, Raden Wisnu Nurcahyo, Beni Ernawan, et al., Open Veterinary Journal, 15:3054-3062. 2025-10-02 14:51:05.
Culex quinquefasciatus is a major vector of filariasis and other mosquito-borne diseases. The sterile insect technique (SIT) has been widely used to suppress mosquito populations, but its effectiveness depends on the dispersal, survival, and competitiveness of sterile males. This study evaluated the dispersal range, survival rate, and recapture success of gamma-irradiated Cx. quinquefasciatus under field conditions. A mark-release-recapture (MRR) experiment was conducted using sterile male and female Cx. quinquefasciatus. Two release events were conducted, and recapture data were collected over seven days using BG-Sentinel-2 traps baited with octanol placed within a 250-m radius. The irradiated males traveled an average of 143.18 m (FR50: 92.78 m; FR90: 220.02 m), and the females dispersed 146.26 m (FR50: 95.26 m; FR90: 227.25 m). Dispersal distance was significantly influenced by release site in males (p = 0.0089) and females (p = 0.0042) but not by recapture day (p > 0.89). Recapture location significantly affected dispersal in both sexes (p < 0.0001). The daily survival probabilities of males and females were 0.88 and 0.69, respectively, with corresponding life expectancies of 7.57 and 2.71 days. The dispersal and survival of sterile Cx. quinquefasciatus are affected by release strategies. To optimize SIT, further studies should refine the marking techniques, explore a combination of trapping methods, and evaluate the dispersal patterns across varied landscapes. These findings offer valuable insights into improving the implementation of SIT for Cx. quinquefasciatus population control.
Estimated cost and operational structure of pgSIT malaria vector control programs in selected West African countries
35203William A.C. Gendron, Robyn Raban, Agastya Mondal, et al., Scientific African, 29. 2025-09-30 15:35:38.
Malaria control has primarily been achieved through vector control, but current methods are insufficient to achieve elimination. Precision guided sterile insect technique (pgSIT) is a mosquito suppression technique that generates sterile male mosquitoes for mass release. Our previous studies showed that this intervention is expected to be highly cost-effective in a malaria endemic region of West Africa, but these estimates used only 15-31% capacity for sex sorting, which is the limiting production step and a primary cost. We, therefore, determined the most cost efficient facility size by calculating the cost per million Anopheles gambiae suppressed as the facility was scaled up to suppress more mosquitoes. We developed an optimized facility size per 9.2 million mosquitoes suppressed, which can be a framework for scaling and increases the cost effectiveness of this intervention. The development of this intervention can potentially interrupt malaria transmission, strengthen local public health institutions, create manufacturing capacity, provide local jobs, and enhance regional health security capabilities that are more resilient to disruptions in supply chains and malaria investment.
The impact of sterile insect technique processes on the performance of tephritid flies
35190Mayren Sánchez-Rosario, Jorge Toledo, Walther Enkerlin, Insect Science, 2025-09-29 09:49:25.
The sterile insect technique (SIT) is a pest control method that has been successful in controlling various species of fruit flies of economic importance worldwide. However, SIT procedures can affect the performance of mass-reared sterile fruit flies, compromising the SIT effectiveness. This review aims to identify and analyze the adverse effects associated with each step of the SIT. Special emphasis is placed on identifying critical points in the SIT process that compromise the quality and highlighting the stages that require greater optimization to improve the effectiveness of the technique. We reviewed the main scientific findings that document the impact of domestication, mass-rearing, irradiation, handling, and release on the biology, ecology, behavior, and genetic makeup of sterile males, and how they affect the performance of sterile males under natural conditions, and the effectiveness of the SIT. Although all stages of the Sterile Insect Technique (SIT) impose some degree of compromise on insect performance, domestication and mass-rearing have the most profoundly negative impact on the field performance of sterile fruit flies. As the initial and most influential stages, they largely determine the overall quality and competitiveness of released insects, exerting a stronger impact than any subsequent SIT component.
The role of the transformer gene in sex determination and its employment in CRISPR/Cas9-based homing gene drive in the global fruit pest Drosophila suzukii
35185Dan Deng, Xueying Yi, Wen Wen, Liuqing He, Wei Peng, Insect Biochemistry and Molecular Biology, 184. 2025-09-29 08:45:13.
Sex determination of Diptera is established by the cascade genes such as transformer (tra), though the primary signals for sex determination differ among different insects. Here, we report the isolation, expression and function of tra gene in an invasive pest, Drosophila suzukii, and study the potential use of the D. suzukii tra (Dstra) gene in CRISPR/Cas9-based homing gene drive for genetic-based pest management. The Dstra gene is highly conserved in structure and has a sex-specific transcript. To test the function of this gene in sex determination, Dstra dsRNA was injected into embryos. Almost all XX embryos developed into masculinized phenotypic male adults with intersex morphology. Abnormal ovaries were revealed in XX pseudomales upon dissection. Based on the necessary role of Dstra for female development, we developed and evaluated a homing gene drive that targets Dstra in D. suzukii. The drive component consisting of multiplex Dstra single guide RNAs and Cas9 with Dsvasa promoter was introduced into the Dstra locus. Abnormal development of both the external genitalia and gonads was observed in G0 and G1 chromosomal female adults that expressed the male-specific doublesex (dsx) transcript. Interestingly, knocking out Dstra led to significantly reduced fertility in adults of corresponding sex and moderate transmission rates of the DsRed gene (63.54 %) were observed. Our results not only confirm the conserved function of the Dstra gene in sex determination, but also highlight the potential of sex conversion-based suppression gene-drive strategy targeting the Dstra gene in controlling of D. suzukii populations.
