Scholarly Literature
This is a database of scholarly literature that concentrates currently on natural and engineered selfish genetic elements (gene drives). The latest are shown here.
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Sterile Insect Technique Programme against Mediterranean Fruit Fly in the Valencian Community (Spain)
16965I. Plá, J. García de Oteyza, C. Tur, M. Á. Martínez, M. C. Laurín, E. Alonso, M. Martínez, Á. Martín, R. Sanchis, M. C. Navarro, M. T. Navarro, R. Argilés, M. Briasco, Ó. Dembilio and V. Dalmau, Insects, 12. 2021-05-04 15:09:26.
The Mediterranean fruit fly, Ceratitis capitata (Wied.), is an endemic pest in fruit-growing areas of the Spanish Mediterranean coast. In the Valencian Community, it represents a serious problem in the cultivation of citrus and numerous species of fruit, such as peach, cherry, apricot, persimmon, etc. For over 50 years, the Department of Agriculture of Valencia has led, promoted, and carried out a C. capitata control programme to protect crops, especially citrus fruits, because this community is the largest national producer and the leading region for fresh citrus exports in the world. Traditionally, pest control has been based on the use of insecticides. However, a reduction of more than 90% of a target wild population was achieved in the frame of a pilot integrated pest management (IPM) project based on the sterile insect technique (SIT), which was implemented from 2003 to 2006. Based on this successful result, in 2007 the Department of Agriculture of Valencia initiated an area-wide integrated pest management (AW-IPM) programme for the suppression of C. capitata, using the SIT as the primary control method. Complementary activities are implemented periodically in hotspots and during different time periods depending on the pest population dynamics. As a result, there has been a reduction of more than 90% in the use of insecticides by aerial means to control C. capitata, as well as a growth trend in exports of citrus and fresh fruits from the Valencian Community in recent years. This paper provides a historical review of the Valencian programme and briefly describes how technological innovations and decision-making tools have contributed to programme efficiency.
Stable isotopes for reliable identification of wild and mass-reared Queensland fruit flies in sterile insect technique programs
17031B. Mainali, A. S. Andrew, P. W. Taylor and P. Rempoulakis, Journal of Pest Science, 14. 2021-05-04 11:12:25.
Queensland fruit fly is one of the most economically important horticultural pests in Australia. Sterile insect technique (SIT) is now being reconsidered and upscaled to combat this pest so reliable discrimination of released sterile Q-flies from wild flies in monitoring traps is important for effective SIT operations. Stable isotopes provide a permanent chemical marker to discriminate sterile and wild flies when dye marking is unclear. In this study, we compared the isotopic ratios of carbon and nitrogen between Q-flies reared on different larval diets and wild flies collected from diverse locations in Australia and New Caledonia. Finally, we conducted a release-recapture study to corroborate differences in stable isotope C and N ratios in laboratory-reared and wild Q-flies. The delta N-15 values obtained from wild and laboratory Q-flies showed high variability that is likely related to the food source of the larval and/or adult stage and do not offer an effective means to discriminate between sterile and wild Q-flies. The delta C-13 values of examined wild Q-flies ranged from - 27.46 to - 24.37 parts per thousand VPDB, whereas those from laboratory-reared, released and recaptured Q-flies ranged from - 25.73 to - 19.26 parts per thousand VPDB. Differences in delta C-13 values resulted in 100% correct classification of wild flies and 96.88% correct classification of released flies. Measurements of intrinsic delta C-13 values offer a precise tool to discriminate between sterile and wild Q-flies in SIT programs, regardless of the composition of the larval or adult pre-release diets.
Living in the endosymbiotic world of Wolbachia: A centennial review
17794R. Kaur, J. D. Shropshire, K. L. Cross, B. Leigh, A. J. Mansueto, V. Stewart, S. R. Bordenstein and S. R. Bordenstein, Cell Host and Microbe, 29:879-893. 2021-05-03 20:31:30.
The most widespread intracellular bacteria in the animal kingdom are maternally inherited endosymbionts of the genus Wolbachia. Their prevalence in arthropods and nematodes worldwide and stunning arsenal of parasitic and mutualistic adaptations make these bacteria a biological archetype for basic studies of symbiosis and applied outcomes for curbing human and agricultural diseases. Here, we conduct a summative, centennial analysis of living in the Wolbachia world. We synthesize literature on Wolbachia's host range, phylogenetic diversity, genomics, cell biology, and applications to filarial, arboviral, and agricultural diseases. We also review the mobilome of Wolbachia including phage WO and its essentiality to hallmark reproductive phenotypes in arthropods. Finally, the Wolbachia system is an exemplar for discovery-based science education using biodiversity, biotechnology, and bioinformatics lessons. As we approach a century of Wolbachia research, the interdisciplinary science of this symbiosis stands as a model for consolidating and teaching the integrative rules of endosymbiotic life.
Genetic Manipulation of Ticks: A Paradigm Shift in Tick and Tick-Borne Diseases Research
17164A. Nuss, A. Sharma and M. Gulia-Nuss, Frontiers in Cellular and Infection Microbiology, 11:7. 2021-05-02 19:18:28.
Ticks are obligate hematophagous arthropods that are distributed worldwide and are one of the most important vectors of pathogens affecting humans and animals. Despite the growing burden of tick-borne diseases, research on ticks has lagged behind other arthropod vectors, such as mosquitoes. This is largely because of challenges in applying functional genomics and genetic tools to the idiosyncrasies unique to tick biology, particularly techniques for stable genetic transformations. CRISPR-Cas9 is transforming non-model organism research; however, successful germline editing has yet to be accomplished in ticks. Here, we review the ancillary methods needed for transgenic tick development and the use of CRISPR/Cas9, the most promising gene-editing approach, for tick genetic transformation.
Mechanistically comparing reproductive manipulations caused by selfish chromosomes and bacterial symbionts
16958E. Dalla Benetta, O. S. Akbari and P. M. Ferree, Heredity, 126:707-716. 2021-05-01 14:52:23.
Insects naturally harbor a broad range of selfish agents that can manipulate their reproduction and development, often leading to host sex ratio distortion. Such effects directly benefit the spread of the selfish agents. These agents include two broad groups: bacterial symbionts and selfish chromosomes. Recent studies have made steady progress in uncovering the cellular targets of these agents and their effector genes. Here we highlight what is known about the targeted developmental processes, developmental timing, and effector genes expressed by several selfish agents. It is now becoming apparent that: (1) the genetic toolkits used by these agents to induce a given reproductive manipulation are simple, (2) these agents target sex-specific cellular processes very early in development, and (3) in some cases, similar processes are targeted. Knowledge of the molecular underpinnings of these systems will help to solve long-standing puzzles and provide new tools for controlling insect pests.
The legal regulation of gene drive technologies
16914C. Elves, Univeristy of Oxford, 2021-05-01 13:32:03.
Gene drive technologies purport to provide a panacea and yet in doing so present unprecedented risks that threaten to change, potentially irreversibly, the way in which we live in the world. Gene drive technologies raise questions about what ends societies ought to seek for their citizens, how they are constituted and how those ends might be attained. Despite this, current discussions surrounding gene drive technologies and their regulation focus almost exclusively on the technical implications. Drawing on the work of sociologists and STS scholars, this thesis argues that lawyers ought to think critically about the ways in which they go about developing their understandings of new technologies as regulatory objects. Lawyers need to evaluate and scrutinize the knowledge claims with which they are presented, and work to identify those extending beyond the required technical expertise, if the regulatory frames they build are to bear fidelity to the realities of the technology. This thesis draws out the regulatory disconnection generated by the current regulation of gene drive technologies through the existing European Union GMO regime. It then goes on to describe the ways in which regulatory reconnection might be achieved by constructing broader frames through which we describe gene drive technologies as a regulatory object. In thinking about how lawyers might go about broadening the frames that they build, this thesis takes examples from Public Health Law scholarship and legislation. In response to both the normative and epistemic lacunae highlighted above, this thesis develops an account of why and how ethical enquiry ought to play a significant role in informing our descriptions of gene drive technologies as regulatory objects. Furthermore, this thesis argues that ethical enquiry is capable of articulating questions to which technical experts must provide answers if we are to develop fuller understandings of the technologies we regulate. In this way, ethical enquiry can help lawyers bridge both the normative and epistemic gaps that they are so often faced with in the regulation of emerging technologies.
Modeling and analysis of the implementation of the Wolbachia incompatible and sterile insect technique for mosquito population suppression.
17098B. Zheng, J. S. Yu and J. Li, Siam Journal on Applied Mathematics, 81:718-740. 2021-04-29 13:06:06.
Mathematical analysis may offer guidance in designing effective mass release strategies for the area-wide application of this Wolbachia incompatible and sterile insect technique in the future. The two most crucial concerns in designing release strategies are how often and in what amount should Wolbachia-infected mosquitoes be released in order to guarantee population suppression. Motivated by the experimental data from the Guangzhou mosquito factory and the release strategy implemented on two islands, we formulate and analyze a mosquito population suppression model considering the situation for the release period T less than the sexual lifespan of Wolbachia-infected males. We define release amount thresholds g(1)* and g(2)* with g(1)* < g(2)*. When the release amount c satisfies c >= g(2)*, population suppression is always achievable, as is mathematically manifested by the global asymptotic stability of the origin. However, when c is an element of (0, g(1)*], we find that suppression can be achieved only if the initial wild mosquito population is small enough. This is mathematically proved by the local asymptotic stability of the origin, together with the existence of exactly two T-periodic solutions, one of which is asymptotically stable and the other of which is unstable, with T being the waiting period between two consecutive releases. For c is an element of (g(1)*, g(2)*), we find sufficient conditions on the nonexistence of T-periodic solution, and the existence of at most two T-periodic solutions.
Selection of Sites for Field Trials of Genetically Engineered Mosquitoes with Gene Drive
16932G. C. Lanzaro, M. Campos, M. Crepeau, A. Cornel, A. Estrada, H. Gripkey, Z. Haddad, A. Kormos, S. Palomares and W. Sharpee, bioRxiv, 2021.04.28.441877. 2021-04-28 15:53:05.
Novel malaria control strategies using genetically engineered mosquitoes (GEMs) are on the horizon. Population modification is one approach wherein mosquitoes are engineered with genes rendering them refractory to the malaria parasite coupled with a low-threshold, Cas9-based gene drive. When released into a wild vector population, GEMs preferentially transmit these beneficial genes to their offspring, ultimately modifying a vector population into a non-vector one. Deploying this technology awaits evaluation including ecologically contained field trials. Here, we consider a process for site selection, the first critical step in designing a trial. Our goal is to identify a site that maximizes prospects for success, minimizes risk, and serves as a fair, valid, and convincing test of efficacy and impacts of a GEM product intended for large-scale deployment in Africa. We base site selection on geographical, geological, and biological, rather than social or legal, criteria. We recognize the latter as critically important but not preeminent. We propose physical islands as being the best candidates for a GEM field trial and present an evaluation of 22 African islands. We consider geographic and genetic isolation, biological complexity, island size, topography, and identify two island groups that satisfy key criteria for ideal GEM field trial sites.Competing Interest StatementThe authors have declared no competing interest.
“Maskandi experience”: exploring the use of a cultural song for community engagement in preparation for a pilot Sterile Insect Technique release programme for malaria vector control in KwaZulu-Natal Province, South Africa 2019
17029P. N. Manana, S. Jewett, J. Zikhali, D. Dlamini, N. Mabaso, Z. Mlambo, R. Ngobese and G. Munhenga, Malaria Journal, 20:11. 2021-04-28 11:06:19.
Background An assessment of the Sterile Insect Technique (SIT) as a complementary malaria vector control tool, is at an advanced stage in South Africa. The technique involves the release of laboratory-reared sterilized male mosquitoes of the major malaria vector Anopheles arabiensis, raising social, ethical and regulatory concerns. Therefore, its implementation largely depends on community participation and acceptance. Against this background, it is critical that robust and effective community strategies are developed. This study describes the development of a cultural song to engage the community and increase awareness on SIT and malaria control in KwaZulu-Natal, South Africa. Methods An exploratory concurrent mixed-methods study was conducted to get opinions about the effectiveness of a cultural song developed to engage communities and increase acceptability of the SIT technology. Two self-administered surveys (expert and community) were conducted. Additionally, more in depth opinions of the song and its effectiveness in conveying the intended information were investigated through three community dialogue sessions with community members in the study area. Results A total of 40 experts and 54 community members participated in the survey. Four themes were identified in relation to the appropriateness and effectiveness of the song, with a fifth theme focused on recommendations for adaptations. Overall, the song was well received with the audience finding it entertaining and informative. Responses to unstructured questions posed after the song showed an increase in the knowledge on malaria transmission and SIT technology. In particular, the explanation that male mosquitoes do not bite allayed anxiety and fears about the SIT technology. Conclusion The song was deemed both culturally appropriate and informative in engaging community members about the SIT technology. It proved useful in promoting health messages and conveying SIT technology as a complementary malaria vector control tool. With minor adaptations, the song has potential as an area-wide community engagement tool in areas targeted for sterile male releases.
Does Gene Technology Offer Potential to Wipe Out Malaria?
16845Anonymous, AFIDEP, 2021-04-25 13:15:13.
The persisting high numbers of Malaria deaths and illnesses mean that the current tools will not get us to zero Malaria. For this reason, experts have continued to explore new tools for Malaria elimination. The gene drive technology is one of the tools being explored for Malaria elimination in Africa. The technology, developed in the past decade, enables precise editing of the genes of living organisms. For Malaria, the technology could be applied to modify the genes of Malaria-causing mosquitoes (the Anopheles) to either reduce their survival or deactivate genes that enable them to carry the Malaria parasite. If successfully applied, scientists believe that gene drive mosquitoes could significantly accelerate the path to Malaria elimination, or zero Malaria. In 2017, the African Union recognized the potential of the gene drive technology in controlling and eliminating Malaria on the continent, and committed to invest in the development and regulation of the technology. This commitment is being implemented by the African Union Development Agency (AUDA/NEPAD), which is currently spearheading efforts to build capacity and support countries to establish the necessary regulatory framework for guiding the research to test the gene drive technology for elimination of Malaria on the continent.
A functional bacteria-derived restriction modification system in the mitochondrion of a heterotrophic protist
16970D. A.-O. Milner, J. A.-O. Wideman, C. A.-O. Stairs, C. D. Dunn and T. A.-O. Richards, PLoS Biology, 2021-04-23 15:33:12.
The overarching trend in mitochondrial genome evolution is functional streamlining coupled with gene loss. Therefore, gene acquisition by mitochondria is considered to be exceedingly rare. Selfish elements in the form of self-splicing introns occur in many organellar genomes, but the wider diversity of selfish elements, and how they persist in the DNA of organelles, has not been explored. In the mitochondrial genome of a marine heterotrophic katablepharid protist, we identify a functional type II restriction modification (RM) system originating from a horizontal gene transfer (HGT) event involving bacteria related to flavobacteria. This RM system consists of an HpaII-like endonuclease and a cognate cytosine methyltransferase (CM). We demonstrate that these proteins are functional by heterologous expression in both bacterial and eukaryotic cells. These results suggest that a mitochondrion-encoded RM system can function as a toxin-antitoxin selfish element, and that such elements could be co-opted by eukaryotic genomes to drive biased organellar inheritance. FAU - Milner, David S
Selfish chromosomal drive shapes recent centromeric histone evolution in monkeyflowers
16833F. R. Finseth, T. C. Nelson and L. Fishman, PLOS Genetics, 17:e1009418. 2021-04-22 14:16:46.
Centromeres must mediate faithful chromosomal transmission during cell division and sexual reproduction, but both the DNA and protein components of centromeres diverge rapidly across species. The selfish centromere model argues that this paradoxical diversity results from a genetic conflict between centromeric DNA variants driving through female meiosis to gain over-transmission and kinetochore proteins co-evolving to re-establish Mendelian segregation. We use whole genome sequencing and genetic crossing experiments to demonstrate active evolutionary interactions between a selfish centromere and a key kinetochore protein (CenH3A) in the wildflower Mimulus guttatus. We show that both inter-specific and intra-population differences in CenH3A affect centromeric drive in hybrids, and that adaptive evolution of CenH3A has followed the recent and costly spread of the driver in a wild population. This work provides novel empirical support for the proposed antagonistic co-evolution of the DNA and protein components of centromeres, with important consequences for understanding cellular function, individual fitness, and species divergence.
Development of Sterile Insect Technique for Control of the European Grapevine Moth, Lobesia botrana, in Urban Areas of Chile
16849G. S. Simmons, M. C. Salazar Sepulveda, E. A. Fuentes Barrios, M. Idalsoaga Villegas, R. E. Medina Jimenez, A. R. Garrido Jerez, R. Henderson and H. Donoso Riffo, Insects, 12. 2021-04-22 13:20:22.
The European grapevine moth, a Palearctic pest, was first detected in the Americas in 2008. Its establishment in Chile presented production and export issues for grapes and other fruits, and a national control campaign was launched. Urban areas next to agricultural production areas were recognized as a challenge for effective control. In 2015, a SIT laboratory was established in Arica, Chile to evaluate its potential for urban control. Progress included the development and evaluation of artificial diets, a mass-rearing of 75,000 moths/week, confirmation of 150 Gy as an operational dose for inherited sterility, and releases of sterile moths in a 25 ha urban area next to fruit production areas. Season-long releases demonstrated that high overflooding ratios were achieved early in the season but decreased with a large increase in the wild moth population. Sterile moth quality was consistently high, and moths were observed living in the field up to 10 days and dispersing up to 800 m. Recommendations for further development of the SIT include conducting cage and field studies to evaluate overflooding ratios and mating competitiveness, measuring of infestation densities in release and no-release areas, and conducting trials to evaluate combining SIT with compatible integrated pest management (IPM) tactics such as fruit stripping and use of mating disruption.
CRISPR-Cas and Its Wide-Ranging Applications: From Human Genome Editing to Environmental Implications, Technical Limitations, Hazards and Bioethical Issues
17324R. Piergentili, A. Del Rio, F. Signore, F. U. Ronchi, E. Marinelli and S. Zaami, Cells, 10:24. 2021-04-21 12:06:42.
The CRISPR-Cas system is a powerful tool for in vivo editing the genome of most organisms, including man. During the years this technique has been applied in several fields, such as agriculture for crop upgrade and breeding including the creation of allergy-free foods, for eradicating pests, for the improvement of animal breeds, in the industry of bio-fuels and it can even be used as a basis for a cell-based recording apparatus. Possible applications in human health include the making of new medicines through the creation of genetically modified organisms, the treatment of viral infections, the control of pathogens, applications in clinical diagnostics and the cure of human genetic diseases, either caused by somatic (e.g., cancer) or inherited (mendelian disorders) mutations. One of the most divisive, possible uses of this system is the modification of human embryos, for the purpose of preventing or curing a human being before birth. However, the technology in this field is evolving faster than regulations and several concerns are raised by its enormous yet controversial potential. In this scenario, appropriate laws need to be issued and ethical guidelines must be developed, in order to properly assess advantages as well as risks of this approach. In this review, we summarize the potential of these genome editing techniques and their applications in human embryo treatment. We will analyze CRISPR-Cas limitations and the possible genome damage caused in the treated embryo. Finally, we will discuss how all this impacts the law, ethics and common sense.
Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes
17062M. L. Kaiser, O. R. Wood, D. Damiens, B. D. Brooke, L. L. Koekemoer and G. Munhenga, Parasites and Vectors, 14:18. 2021-04-19 13:57:18.
The Anopheles gambiae complex and An. funestus group species made up the majority of wild collections along with other anophelines. The An. arabiensis population size was estimated to be between 550 and 9500 males per hectare depending on time of year, weather conditions and method used. Average dispersal distance of marked males ranged from 58 to 86 m. Marked males were found in swarms with wild males, indicating that laboratory-reared males are able to locate and participate in mating swarms. Conclusions It was logistically feasible to conduct mark-release-recapture studies at the current scale. The population size estimates obtained may provide a guideline for the initial number of males to use for a pending SIT pilot trial. It is promising for future SIT trials that laboratory-reared marked males participated in natural swarms, appearing at the right place at the right time.
Engineered sex ratio distortion by X-shredding in the global agricultural pest Ceratitis capitata
16837A. Meccariello, F. Krsticevic, R. Colonna, G. Del Corsano, B. Fasulo, P. A. Papathanos and N. Windbichler, BMC Biology, 19:78. 2021-04-16 14:29:21.
Genetic sex ratio distorters are systems aimed at effecting a bias in the reproductive sex ratio of a population and could be applied for the area-wide control of sexually reproducing insects that vector disease or disrupt agricultural production. One example of such a system leading to male bias is X-shredding, an approach that interferes with the transmission of the X-chromosome by inducing multiple DNA double-strand breaks during male meiosis. Endonucleases targeting the X-chromosome and whose activity is restricted to male gametogenesis have recently been pioneered as a means to engineer such traits.
The Insect Pest Control Laboratory of the Joint FAO/IAEA Programme: Ten Years (2010–2020) of Research and Development, Achievements and Challenges in Support of the Sterile Insect Technique
16702M. J. B. Vreysen, A. M. M. Abd-Alla, K. Bourtzis, J. Bouyer, C. Caceres, C. de Beer, D. Oliveira Carvalho, H. Maiga, W. Mamai, K. Nikolouli, H. Yamada and R. Pereira, Insects, 12. 2021-04-13 15:29:17.
The Joint FAO/IAEA Centre (formerly called Division) of Nuclear Techniques in Food and Agriculture was established in 1964 and its accompanying laboratories in 1961. One of its subprograms deals with insect pest control, and has the mandate to develop and implement the sterile insect technique (SIT) for selected key insect pests, with the goal of reducing the use of insecticides, reducing animal and crop losses, protecting the environment, facilitating international trade in agricultural commodities and improving human health.
Introduction of a cold sensitivity-conferring mutation into the RTA-Bddsx hybrid system of Bactrocera dorsalis for establishment of a thermally controllable homozygous line
17327S. M. Dai, C. Y. Huang and C. Chang, Pest Management Science, 7. 2021-04-10 14:40:01.
BACKGROUND For efficient control of the economically important fruit pest Bactrocera dorsalis, a hybrid system combining ricin toxicity and sex-related alternative splicing of the doublesex gene has been developed. This system exhibits the expected female-specific lethal effect; however, the transgenic females do not survive, making it difficult to raise stable homozygous lines. Since modification of ricin toxin A chain (RTA) through a single-residue change (Gly(212) > Arg(212)) leads to cold-sensitive posttranslational repression of its toxicity, we utilized this unique property to obtain RTA-Bddsx females that survive at low temperature for line maintenance. RESULTS In transient expression experiments using embryonic injection, two groups treated with RTAcs-derived DNA (LERQcs and RTAcs) exhibited temperature-dependent effects. The toxicity was higher at 29 degrees C than at 18 degrees C. The proportion of males was close to 50% at 18 degrees C in all the tested groups except LERQcs-treated flies, which exhibited a high proportion of males (over 70%) at 29 degrees C. The results indicate the cold-sensitive responses of RTA and further suggest a female-specific lethal effect. Subsequently, 14 putative RTAcs-Bddsx transgenic Ds-Red(+) G(1) males were identified, and female-specific lethal effects were observed in Ds-Red(+) G(2) and G(3) lines under cultivation at 29 degrees C but not at 18 degrees C. The male ratio can be increased to up to 95% in G(3) line 001, indicating that RTAcs functions well in B. dorsalis. CONCLUSION The improved RTAcs-Bddsx system with conditional toxicity represents a novel and promising step toward the practical control of B. dorsalis.
Evidence for natural hybridization and novel Wolbachia strain superinfections in the Anopheles gambiae complex from Guinea
16990C. L. Jeffries, C. Cansado-Utrilla, A. H. Beavogui, C. Stica, E. K. Lama, M. Kristan, S. R. Irish and T. Walker, Royal Society Open Science, 8:18. 2021-04-07 14:55:09.
Wolbachia, a widespread bacterium which can influence mosquito-borne pathogen transmission, has recently been detected within Anopheles (An.) species that are malaria vectors in Sub-Saharan Africa. Although studies have reported Wolbachia strains in the An. gambiae complex, apparent low density and prevalence rates require confirmation. In this study, wild Anopheles mosquitoes collected from two regions of Guinea were investigated. In contrast with previous studies, RNA was extracted from adult females (n = 516) to increase the chances for the detection of actively expressed Wolbachia genes, determine Wolbachia prevalence rates and estimate relative strain densities. Molecular confirmation of mosquito species and Wolbachia multilocus sequence typing (MLST) were carried out to analyse phylogenetic relationships of mosquito hosts and newly discovered Wolbachia strains. Strains were detected in An. melas (prevalence rate of 11.6%-16/138) and hybrids between An. melas and An. gambiae sensu stricto (prevalence rate of 40.0%-6/15) from Senguelen in the Maferinyah region. Furthermore, a novel high-density strain, termed wAnsX, was found in an unclassified Anopheles species. The discovery of novel Wolbachia strains (particularly in members, and hybrids, of the An. gambiae complex) provides further candidate strains that could be used for future Wolbachia-based malaria biocontrol strategies.
CRISPR-mediated knock-in of transgenes into the malaria vector Anopheles funestus
16674C. Quinn, A. Anthousi, C. Wondji and T. Nolan, bioRxiv, 2021.03.31.437891. 2021-03-31 13:57:08.
We describe herein an optimised transformation system based on the germline delivery of CRISPR components that allows efficient cleavage of a previously validated genomic site and preferential repair of these cut sites via homology-directed repair (HDR), which allows introduction of exogenous template sequence, rather than end-joining repair. The rates of transformation achieved are sufficiently high that it should be able to introduce alleles of choice to a target locus, and recover these, without the need to include additional dominant marker genes. Moreover, the high rates of HDR observed suggest that gene drives, which employ an HDR-type mechanism to ensure their proliferation in the genome, may be well suited to work in An. funestus.Competing Interest StatementThe authors have declared no competing interest.
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