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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Centromere drive: model systems and experimental progress
23148D. Dudka and M. A. Lampson, Chromosome Research, 2022-06-22 09:28:53.
Centromeres connect chromosomes and spindle microtubules to ensure faithful chromosome segregation. Paradoxically, despite this conserved function, centromeric DNA evolves rapidly and centromeric proteins show signatures of positive selection. The centromere drive hypothesis proposes that centromeric DNA can act like a selfish genetic element and drive non-Mendelian segregation during asymmetric female meiosis. Resulting fitness costs lead to genetic conflict with the rest of the genome and impose a selective pressure for centromeric proteins to adapt by suppressing the costs. Here, we describe experimental model systems for centromere drive in yellow monkeyflowers and mice, summarize key findings demonstrating centromere drive, and explain molecular mechanisms. We further discuss efforts to test if centromeric proteins are involved in suppressing drive-associated fitness costs, highlight a model for centromere drive and suppression in mice, and put forth outstanding questions for future research.
Sensitivity of wMel and wAlbB Wolbachia infections in Aedes aegypti Puducherry (Indian) strains to heat stress during larval development
23056K. Gunasekaran, C. Sadanandane, D. Panneer, A. Kumar, M. Rahi, S. Dinesh, B. Vijayakumar, M. Krishnaraja, S. K. Subbarao and P. Jambulingam, Parasites and Vectors, 15:221. 2022-06-21 15:19:54.
BACKGROUND: ICMR-Vector Control Research Centre, Puducherry, India, developed two colonies of Aedes aegypti infected with wMel and wAlbB Wolbacia strains called Ae. aegypti (Pud) lines for dengue control. The sensitivity of wMel and wAlbB strains in Ae. aegypti (Pud) lines to heat stress was studied. METHODS: wMel and wAlbB infected and uninfected Ae. aegypti larvae (first to fourth instars) were reared in the laboratory to adults at 26 °C, 30 °C, 36 °C and 40 °C constant temperatures and also 26-30 °C, 26-36 °C and 26-40 °C diurnal cyclic temperatures. The adults were tested for Wolbachia infection. Experiments were also carried out rearing the larvae under simulated field conditions in summer (April and June) under sunlight using fully open and half open bowls and also under sunlight and natural shade. RESULTS: At 36 °C and 40 °C constant temperatures, complete larval mortality was observed. At 30 °C and 26 °C, no larval mortality occurred, but Wolbachia density was relatively low in wMel infected males compared to control (maintained at 26 ± 1 °C). At diurnal cyclic temperature of 26-40 °C, Wolbachia density was reduced in males of both the (Pud) lines, but not in females. At 26-36 °C, reduction in Wolbachia density was observed in wMel males but not in wAlbB males. At 26-30 °C, no significant reduction in Wolbachia density was observed with wMel and wAlbB strains. In simulated field conditions (April), under sunlight, the daytime water temperature reached a maximum of 35.7 °C in both full and half open bowls. No larval mortality occurred. Wolbachia frequency and density was reduced in wMel-infected Ae. aegypti (Pud) males from both type of bowls and in females from full open bowls, and in wAlbB males from half open bowls. In June, rearing of larvae under sunlight, the first-instar larvae experienced a maximum daytime water temperature of > 38 °C that caused complete mortality. No larval mortality was observed in bowls kept under shade (< 32 °C). CONCLUSIONS: Exposure of larvae to higher rearing temperatures in the laboratory and simulated-field conditions reduced the densities of wMel and wAlbB strains particularly in males, but the impact was more pronounced for wMel strain. The actual effect of heat stress on the stability of these two Wolbachia strains needs to be tested under natural field conditions.
Sexual transmission of Anopheles gambiae densovirus (AgDNV) leads to disseminated infection in mated females
23030K. L. Werling, R. M. Johnson, H. C. Metz and J. L. Rasgon, Parasites and Vectors, 15:219. 2022-06-20 07:20:44.
Anopheles gambiae densovirus (AgDNV) is an insect-specific, single-stranded DNA virus that infects An. gambiae sensu stricto (s.s.), the major mosquito species responsible for transmitting malaria parasites throughout sub-Saharan Africa. AgDNV is a benign virus that is very specific to its mosquito host and therefore has the potential to serve as a vector control tool via paratransgenesis (genetic modification of mosquito symbionts) to limit transmission of human pathogens. Prior to being engineered into a control tool, the natural transmission dynamics of AgDNV between An. gambiae mosquitoes needs to be fully understood. Additionally, improved knowledge of AgDNV infection in male mosquitoes is needed. In the study presented here, we examined the tissue tropism of AgDNV in the male reproductive tract and investigated both venereal and vertical transmission dynamics of the virus.
Hoisted with his own petard: how sex-ratio meiotic drive in <em>Drosophila affinis</em> creates resistance alleles that limit its spread
23231W.-J. Ma, E. M. Knoles, K. B. Patch, M. M. Shoaib and R. L. Unckless, bioRxiv, 2022.02.14.480432. 2022-06-19 06:28:31.
Meiotic drivers are selfish genetic elements that tinker with gametogenesis to bias their own transmission into the next generation of offspring. Such tinkering can have significant consequences on gametogenesis and end up hampering the spread of the driver. In Drosophila affinis, sex-ratio meiotic drive is caused by an X-linked complex that, when in males with a susceptible Y chromosome, results in broods that are typically more than 95% female. Interestingly, D. affinis males lacking a Y chromosome (XO) are fertile and males with the meiotic drive X and no Y produce only sons - effectively reversing the sex-ratio effect. Here, we show that meiotic drive dramatically increases the rate of nondisjunction of the Y chromosome (at least 750X), meaning that the driver is creating resistant alleles through the process of driving. We then model how the O might influence the spread, dynamics and equilibrium of the sex-ratio X chromosome. We find that the O can prevent the spread or reduce the equilibrium frequency of the sex-ratio X chromosome and it can even lead to oscillations in frequency. Finally, with reasonable parameters, the O is unlikely to lead to the loss of the Y chromosome, but we discuss how it might lead to sex-chromosome turnover indirectly.Competing Interest StatementThe authors have declared no competing interest.
DriverSEAT: A spatially-explicit stochastic modelling framework for the evaluation of gene drives in novel target species
23008M. Legros and L. G. Barrett, bioRxiv, 2022.06.13.496025. 2022-06-16 08:19:49.
Gene drives represent a potentially ground breaking technology for the control of undesirable species or the introduction of desirable traits in wild population, and there is strong interest in applying these technologies to a wide range of species across many domains including agriculture, health, conservation and biosecurity. There remains however considerable uncertainty regarding the feasibility and efficacy of gene drives in various species, based in particular on biological and ecological specificities of each target. In this paper we introduce DriverSEAT, a new spatial, modular modelling framework designed to assess the outcome of gene drives in a range of target species based on their specific ecological dynamics and genetics. In addition to the main structure and characteristics of the model, we present an example of its application on scenarios of genetic control of weeds, a potential candidate for gene drive control that presents significant challenges associated with plant population dynamics. We illustrate here how the results from DriverSEAT can inform on the potential value of gene drives in this specific context, and generally provide ecologically informed guidance for the development and feasibility of gene drives as a control method in new target species.Competing Interest StatementThe authors have declared no competing interest.
Genetic Approaches for Controlling CRISPR-based Autonomous Homing Gene Drives
23115P. R. Chennuri, Z. N. Adelman and K. M. Myles, Frontiers in Bioengineering and Biotechnology, 10:897231. 2022-06-15 08:41:17.
CRISPR-based autonomous homing gene drives are a potentially transformative technology with the power to reduce the prevalence of, or even eliminate, vector-borne diseases, agricultural pests, and invasive species. However, there are a number of regulatory, ethical, environmental, and sociopolitical concerns surrounding the potential use of gene drives, particularly regarding the possibility for any unintended outcomes that might result from such a powerful technology. Therefore, there is an imminent need for countermeasures or technologies capable of exerting precise spatiotemporal control of gene drives, if their transformative potential is ever to be fully realized. This review summarizes the current state of the art in the development of technologies to prevent the uncontrolled spread of CRISPR-based autonomous homing gene drives.
Natural and Engineered Sex Ratio Distortion in Insects
23010A. Compton and Z. Tu, Frontiers in Ecology and Evolution, 10. 2022-06-15 08:25:52.
Insects have evolved highly diverse genetic sex-determination mechanisms and a relatively balanced male to female sex ratio is generally expected. However, selection may shift the optimal sex ratio while meiotic drive and endosymbiont manipulation can result in sex ratio distortion (SRD). Recent advances in sex chromosome genomics and CRISPR/Cas9-mediated genome editing brought significant insights into the molecular regulators of sex determination in an increasing number of insects and provided new ways to engineer SRD. We review these advances and discuss both naturally occurring and engineered SRD in the context of the Anthropocene. We emphasize SRD-mediated biological control of insects to help improve One Health, sustain agriculture, and conserve endangered species.
Meiotic behavior, transmission and active genes of B chromosomes in the cichlid Astatotilapia latifasciata: new clues about nature, evolution and maintenance of accessory elements
22951A. L. Cardoso, N. B. Venturelli, I. da Cruz, F. M. de Sá Patroni, D. de Moraes, R. A. de Oliveira, R. Benavente and C. Martins, Molecular Genetics and Genomics, 2022-06-15 06:37:12.
Supernumerary B chromosomes (Bs) are dispensable genetic elements widespread in eukaryotes and are poorly understood mainly in relation to mechanisms of maintenance and transmission. The cichlid Astatotilapia latifasciata can harbor Bs in a range of 0 (named B -) and 1-2 (named B +). The B in A. latifasciata is rich in several classes of repetitive DNA sequences, contains protein coding genes, and affects hosts in diverse ways, including sex-biased effects. To advance in the knowledge about the mechanisms of maintenance and transmission of B chromosomes in A. latifasciata, here, we studied the meiotic behavior in males and transmission rates of A. latifasciata B chromosome. We also analyzed structurally and functionally the predicted B chromosome copies of the cell cycle genes separin-like, tubb1-like and kif11-like. We identified in the meiotic structure relative to the B chromosome the presence of proteins associated with Synaptonemal Complex organization (SMC3, SYCP1 and SYCP3) and found that the B performs self-pairing. These data suggest that isochromosome formation was a step during B chromosome evolution and this element is in a stage of diversification of the two arms keeping the self-pairing behavior to protect the A chromosome complement of negative effects of recombination. Moreover, we observed no occurrence of B-drive and confirmed the presence of cell cycle genes copies in the B chromosome and their transcription in encephalon, muscle and gonads, which can indicates beneficial effects to hosts and contribute to B maintenance.
Generation of Gene Drive Mice for Invasive Pest Population Suppression
22890M. D. Bunting, C. Pfitzner, L. Gierus, M. White, S. Piltz and P. Q. Thomas, Applications of Genome Modulation and Editing, 2022-06-14 06:00:54.
Gene drives are genetic elements that are transmitted to greater than 50% of offspring and have potential for population modification or suppression. While gene drives are known to occur naturally, the recent emergence of CRISPR-Cas9 genome-editing technology has enabled generation of synthetic gene drives in a range of organisms including mosquitos, flies, and yeast. For example, studies in Anopheles mosquitos have demonstrated >95% transmission of CRISPR-engineered gene drive constructs, providing a possible strategy for malaria control. Recently published studies have also indicated that it may be possible to develop gene drive technology in invasive rodents such as mice. Here, we discuss the prospects for gene drive development in mice, including synthetic “homing drive” and X-shredder strategies as well as modifications of the naturally occurring t haplotype. We also provide detailed protocols for generation of gene drive mice through incorporation of plasmid-based transgenes in a targeted and non-targeted manner. Importantly, these protocols can be used for generating transgenic mice for any project that requires insertion of kilobase-scale transgenes such as knock-in of fluorescent reporters, gene swaps, overexpression/ectopic expression studies, and conditional “floxed” alleles.
Selective targeting of biting females to control mosquito-borne infectious diseases
22953B. B. Kojin, A. Compton, Z. N. Adelman and Z. Tu, Trends in Parasitology, 2022-06-13 06:48:00.
Mosquitoes are vectors for a number of infectious diseases. Only females feed on blood to provision for their embryos and, in doing so, transmit pathogens to the associated vertebrate hosts. Therefore, sex is an important phenotype in the context of genetic control programs, both for sex separation in the rearing facilities to avoid releasing biting females and for ways to distort the sex ratio towards nonbiting males. We review recent progress in the fundamental knowledge of sex determination and sex chromosomes in mosquitoes and discuss new methods to achieve sex separation and sex ratio distortion to help control mosquito-borne infectious diseases. We conclude by suggesting a few critical areas for future research.
Male-killing-associated bacteriophage WO identified from comparisons of Wolbachia endosymbionts of Homona magnanima
22901H. Arai, H. Anbutsu, Y. Nishikawa, M. Kogawa, K. Ishii, M. Hosokawa, S.-R. Lin, M. Ueda, M. Nakai, Y. Kunimi, T. Harumoto, D. Kageyama, H. Takeyama and M. N. Inoue, bioRxiv, 2022-06-13 06:22:33.
The origin and mechanism of male-killing, an advantageous strategy employed by maternally transmitted symbionts such as Wolbachia, remain unclear. We compared genomes of four Wolbachia strains derived from Homona magnanima, a male-killing strain wHm-t (1.5 Mb), and three non-male-killing strains, wHm-a (1.1 Mb), wHm-b (1.3 Mb), and wHm-c (1.4 Mb). A wHm-t-specific 76-kbp prophage region harboured two tandemly arrayed WO-mediated killing (wmk) gene homologs (wmk-1/wmk-2 and wmk-3/wmk-4). Of these, wmk-1 or wmk-3 killed almost all Drosophila melanogaster individuals when transgenically overexpressed. Dual expression of wmk-3 and wmk-4 killed all males and rescued females. We propose a novel hypothesis wherein horizontally transmitted proto-Wolbachia with a single wmk killed both sexes, and tandem duplication of wmk allowed an evolutionary transition to a vertically transmitted symbiont, causing male-killing. Our study highlights the bacteriophage as a critical driver of the evolution of male-killing and argues for a conserved male-killing mechanism in diverse insects.Competing Interest StatementThe authors have declared no competing interest.
Iterative evolution of supergene-based social polymorphism in ants
22899T. Kay, Q. Helleu and L. Keller, Philos Trans R Soc Lond B Biol Sci, 377:20210196. 2022-06-13 06:17:44.
Species commonly exhibit alternative morphs, with individual fate being determined during development by either genetic factors, environmental cues or a combination thereof. Ants offer an interesting case study because many species are polymorphic in their social structure. Some colonies contain one queen while others contain many queens. This variation in queen number is generally associated with a suite of phenotypic and life-history traits, including mode of colony founding, queen lifespan, queen-worker dimorphism and colony size. The basis of this social polymorphism has been studied in five ant lineages, and remarkably social morph seems to be determined by a supergene in all cases. These 'social supergenes' tend to be large, having formed through serial inversions, and to comprise hundreds of linked genes. They have persisted over long evolutionary timescales, in multiple lineages following speciation events, and have spread between closely related species via introgression. Their evolutionary dynamics are unusually complex, combining recessive lethality, spatially variable selection, selfish genetic elements and non-random mating. Here, we synthesize the five cases of supergene-based social polymorphism in ants, highlighting interesting commonalities, idiosyncrasies and implications for the evolution of polymorphisms in general. This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.
Unbalanced selection: the challenge of maintaining a social polymorphism when a supergene is selfish
22895A. G. Tafreshi, S. P. Otto and M. Chapuisat, Philos Trans R Soc Lond B Biol Sci, 377:20210197. 2022-06-13 06:11:36.
Supergenes often have multiple phenotypic effects, including unexpected detrimental ones, because recombination suppression maintains associations among co-adapted alleles but also allows the accumulation of recessive deleterious mutations and selfish genetic elements. Yet, supergenes often persist over long evolutionary periods. How are such polymorphisms maintained in the face of selection, drive and drift? We present a population genetic model that investigates the conditions necessary for a stable polymorphic equilibrium when one of the supergene haplotypes is a selfish genetic element. The model fits the characteristics of the Alpine silver ant, Formica selysi, in which a large supergene underlies colony social organization, and one haplotype distorts Mendelian transmission by killing progeny that did not inherit it. The model shows that such maternal-effect killing strongly limits the maintenance of social polymorphism. Under random mating, transmission ratio distortion prevents rare single-queen colonies from invading populations of multiple-queen colonies, regardless of the fitness of each genotype. A stable polymorphic equilibrium can, however, be reached when high rates of assortative mating are combined with large fitness differences among supergene genotypes. The model reveals that the persistence of the social polymorphism is non-trivial and expected to occur only under restrictive conditions that deserve further empirical investigation. This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.
Supergene potential of a selfish centromere
22893F. Finseth, K. Brown, A. Demaree and L. Fishman, Philos Trans R Soc Lond B Biol Sci, 377:20210208. 2022-06-13 06:07:46.
Selfishly evolving centromeres bias their transmission by exploiting the asymmetry of female meiosis and preferentially segregating to the egg. Such female meiotic drive systems have the potential to be supergenes, with multiple linked loci contributing to drive costs or enhancement. Here, we explore the supergene potential of a selfish centromere (D) in Mimulus guttatus, which was discovered in the Iron Mountain (IM) Oregon population. In the nearby Cone Peak population, D is still a large, non-recombining and costly haplotype that recently swept, but shorter haplotypes and mutational variation suggest a distinct population history. We detected D in five additional populations spanning more than 200 km; together, these findings suggest that selfish centromere dynamics are widespread in M. guttatus. Transcriptome comparisons reveal elevated differences in expression between driving and non-driving haplotypes within, but not outside, the drive region, suggesting large-scale cis effects of D's spread on gene expression. We use the expression data to refine linked candidates that may interact with drive, including Nuclear Autoantigenic Sperm Protein (NASP(SIM3)), which chaperones the centromere-defining histone CenH3 known to modify Mimulus drive. Together, our results show that selfishly evolving centromeres may exhibit supergene behaviour and lay the foundation for future genetic dissection of drive and its costs. This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.
Mendel’s First Law: partisan interests and the parliament of genes
23006C. Veller, Heredity, 2022-06-11 07:51:41.
Mendel’s First Law requires explanation because of the possibility of ‘meiotic drivers’, genes that distort fair segregation for selfish gain. The suppression of drive, and the restoration of fair segregation, is often attributed to genes at loci unlinked to the drive locus—such genes cannot benefit from drive but do suffer its associated fitness costs. However, selection can also favour suppressors at loci linked to the drive locus, raising the question of whether suppression of drive usually comes from linked or unlinked loci. Here, I study linked and unlinked suppression in a two-locus model with initial stable polymorphism at the drive locus. I find that the invasion rate of suppressors is a decreasing function of the recombination fraction between the drive and suppressor loci. Surprisingly, the relative likelihood of unlinked vs. linked suppression increases with the strength of drive and is insensitive to the fitness costs of the driver allele. I find that the chromosomal position of the driver influences how rapidly it is suppressed, with a driver in the middle of a chromosome suppressed more rapidly than a driver near the tip. When drive is strong, only a small number of chromosomes are required for suppression usually to derive from unlinked loci. In contrast, when drive is weak, and especially when suppressor alleles are associated with fitness costs, suppression will usually come from linked loci unless the genome comprises many chromosomes.
Current Status of Mosquito Handling, Transporting and Releasing in Frame of the Sterile Insect Technique
22868J. Guo, X. Zheng, D. Zhang and Y. Wu, Insects, 13. 2022-06-10 07:44:12.
The sterile insect technique (SIT) and its related technologies are considered to be a powerful weapon for fighting against mosquitoes. As an important part of the area-wide integrated pest management (AW-IPM) programs, SIT can help reduce the use of chemical pesticides for mosquito control, and consequently, the occurrence of insecticide resistance. The mosquito SIT involves several important steps, including mass rearing, sex separation, irradiation, packing, transportation, release and monitoring. To enable the application of SIT against mosquitoes to reduce vector populations, the Joint Food and Agriculture Organization of the United Nations (FAO) and the International Atomic Energy Agency (IAEA) Centre (previously called Division) of Nuclear Techniques in Food and Agriculture (hereinafter called Joint FAO/IAEA Centre) and its Insects Pest Control sub-program promoted a coordinated research project (CRP) entitled “Mosquito handling, transport, release and male trapping methods” to enhance the success of SIT. This article summarizes the existing explorations that are critical to the handling and transporting of male mosquitoes, offers an overview of detailed steps in SIT and discusses new emerging methods for mosquito releases, covering most processes of SIT.
Active genetics comes alive
22888V. M. Gantz and E. Bier, BioEssays, 2022-06-09 09:28:52.
Abstract Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based ?active genetic? elements developed in 2015 bypassed the fundamental rules of traditional genetics. Inherited in a super-Mendelian fashion, such selfish genetic entities offered a variety of potential applications including: gene-drives to disseminate gene cassettes carrying desired traits throughout insect populations to control disease vectors or pest species, allelic drives biasing inheritance of preferred allelic variants, neutralizing genetic elements to delete and replace or to halt the spread of gene-drives, split-drives with the core constituent Cas9 endonuclease and guide RNA (gRNA) components inserted at separate genomic locations to accelerate assembly of complex arrays of genetic traits or to gain genetic entry into novel organisms (vertebrates, plants, bacteria), and interhomolog based copying systems in somatic cells to develop tools for treating inherited or infectious diseases. Here, we summarize the substantial advances that have been made on all of these fronts and look forward to the next phase of this rapidly expanding and impactful field.
Genetically Modified Mosquitoes to Fight Malaria in Nigeria, Burkina Faso, Mali and Uganda: What Legal Response?
23275O. J. L. Tung, Potchefstroom Electronic Law Journal, 25:1-42. 2022-06-07 10:05:47.
Advanced applied research on genetically modified (hereafter GM) insects is being undertaken to control insect vectors of human diseases such as mosquitoes. GM insect technologies are being developed in countries where there is a legal framework for genetically modified mosquitoes (hereafter GMM), but the beneficiaries of such insect technologies to control insect-borne diseases are most likely to be in malaria-endemic countries where the regulation of GM insect technologies is inadequate. Although no commercial release of GMM has been conducted in Africa yet, there may be prospects for the use of GMM to control malaria in malaria-endemic countries such as Nigeria, Burkina Faso, Mali and Uganda. Nigeria has the highest rate of deaths related to malaria in Africa and will potentially be targeted by companies seeking to introduce GMM as a public health tool in African countries. Research is being carried out on GMM in Burkina Faso, Mali and Uganda in collaboration with foreign companies. Whereas the control of diseases is certainly needed and there are potential public health benefits for GM insect technologies to address mosquito control, there are environmental and health concerns, and there is also the potential of the misuse of such technologies. Consequently, the use of GMM requires prior robust domestic, regional and international regulation. While the Cartagena Protocol on Transboundary Movements of Living Modified Organisms (LMOs) to the Convention on Biological Diversity (hereafter the Cartagena Protocol)and voluntary guidelines on the testing of GM mosquitoes are applicable with respect to GM insect technologies, there is a lack of international and regional guidance on the regulation of such technologies. Domestic legislation tends to focus on GM crops and is inadequate for regulating GMM. This paper discusses the legal response for the above Africancountries which may perhaps use GMM as a public health tool and makes recommendations for the necessary regulatory response
Investigating CRISPR/Cas9 gene drive for production of disease-preventing prion gene alleles
22796A. R. Castle, S. Wohlgemuth, L. Arce and D. Westaway, PLoS One, 17:e0269342. 2022-06-07 09:14:53.
Prion diseases are a group of fatal neurodegenerative disorders that includes chronic wasting disease, which affects cervids and is highly transmissible. Given that chronic wasting disease prevalence exceeds 30% in some endemic areas of North America, and that eventual transmission to other mammalian species, potentially including humans, cannot be ruled out, novel control strategies beyond population management via hunting and/or culling must be investigated. Prion diseases depend upon post-translational conversion of the cellular prion protein, encoded by the Prnp gene, into a disease-associated conformation; ablation of cellular prion protein expression, which is generally well-tolerated, eliminates prion disease susceptibility entirely. Inspired by demonstrations of gene drive in caged mosquito species, we aimed to test whether a CRISPR/Cas9-based gene drive mechanism could, in principle, promote the spread of a null Prnp allele among mammalian populations. First, we showed that transient co-expression of Cas9 and Prnp-directed guide RNAs in RK13 cells generates indels within the Prnp open-reading frame, indicating that repair of Cas9-induced double-strand breaks by non-homologous end-joining had taken place. Second, we integrated a ~1.2 kb donor DNA sequence into the Prnp open-reading frame in N2a cells by homology-directed repair following Cas9-induced cleavages and confirmed that integration occurred precisely in most cases. Third, we demonstrated that electroporation of Cas9/guide RNA ribonucleoprotein complexes into fertilised mouse oocytes resulted in pups with a variety of disruptions to the Prnp open reading frame, with a new coisogenic line of Prnp-null mice obtained as part of this work. However, a technical challenge in obtaining expression of Cas9 in the male germline prevented implementation of a complete gene drive mechanism in mice.
Retraction Note: Selective inheritance of target genes from only one parent of sexually reproduced F1 progeny in Arabidopsis
22794T. Zhang, M. Mudgett, R. Rambabu, B. Abramson, X. Dai, T. P. Michael and Y. Zhao, Nature Communications, 13:3270. 2022-06-07 08:36:48.
Retraction to: Nature Communications https://doi-org.proxy-um.researchport.umd.edu/10.1038/s41467-021-24195-5, published online 22 June 2021.We retract the article cited above because genotyping results from recent experiments are not consistent with the conclusions presented in the paper.We recently genotyped a selection of F2 plants in order to identify plants to use for an introgression experiment.In the original study, we confirmed homozygosity by using a pair of oligonucleotides covering the large gene drive region in its entirety, a region that is too large to be amplified by PCR if both alleles have integrated the gene drive element. When we analyzed F2 plants using a pair of oligonucleotides targeting a smaller region of the gene drive, we found a small fragment was amplified only in about 75% of the plants. The absence of the band in the remaining F2 plants can be accounted for by a large NHEJ based deletion in one of the alleles of the F1 plants, which can result in the removal of the oligonucleotide binding sites. Thus, the F1 plants presented in the paper are not homozygous as stated in the published paper.In light of the new genotyping data that invalidate our conclusions on gene drives, we are retracting the paper. The gene targeting results of both the CRY1 lines and NPY5-GFP lines remain valid. We apologize for any inconvenience the publication of this work may have caused to the scientific community. All authors agree to the retraction.
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