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Devos Y, Mumford JD, Bonsall MB, Camargo AM, Firbank LG, Glandorf DCM, Nogué F, Paraskevopoulos K, Wimmer EA. Potential use of gene drive modified insects against disease vectors, agricultural pests and invasive species poses new challenges for risk assessment. Crit Rev Biotechnol 2021; 42:254-270. [PMID: 34167401 DOI: 10.1080/07388551.2021.1933891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Potential future application of engineered gene drives (GDs), which bias their own inheritance and can spread genetic modifications in wild target populations, has sparked both enthusiasm and concern. Engineered GDs in insects could potentially be used to address long-standing challenges in control of disease vectors, agricultural pests and invasive species, or help to rescue endangered species, and thus provide important public benefits. However, there are concerns that the deliberate environmental release of GD modified insects may pose different or new harms to animal and human health and the wider environment, and raise novel challenges for risk assessment. Risk assessors, risk managers, developers, potential applicants and other stakeholders at many levels are currently discussing whether there is a need to develop new or additional risk assessment guidance for the environmental release of GD modified organisms, including insects. Developing new or additional guidance that is useful and practical is a challenge, especially at an international level, as risk assessors, risk managers and many other stakeholders have different, often contrasting, opinions and perspectives toward the environmental release of GD modified organisms, and on the adequacy of current risk assessment frameworks for such organisms. Here, we offer recommendations to overcome some of the challenges associated with the potential future development of new or additional risk assessment guidance for GD modified insects and provide considerations on areas where further risk assessment guidance may be required.
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Affiliation(s)
- Yann Devos
- GMO Unit, European Food Safety Authority (EFSA), Parma, Italy
| | - John D Mumford
- Centre for Environmental Policy, Imperial College London, Ascot, UK
| | | | - Ana M Camargo
- GMO Unit, European Food Safety Authority (EFSA), Parma, Italy
| | | | - Debora C M Glandorf
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Fabien Nogué
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | | | - Ernst A Wimmer
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, GZMB, Georg August University, Göttingen, Germany
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Sutter A, Price TA, Wedell N. The impact of female mating strategies on the success of insect control technologies. CURRENT OPINION IN INSECT SCIENCE 2021; 45:75-83. [PMID: 33601059 DOI: 10.1016/j.cois.2021.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/11/2021] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Attempts to control insect pests and disease vectors have a long history. Recently, new technology has opened a whole new range of possible methods to suppress or transform natural populations. But it has also become clear that a better understanding of the ecology of targeted populations is needed. One key parameter is mating behaviour. Often modified males are released which need to successfully reproduce with females while competing with wild males. Insect control techniques can be affected by target species' mating ecology, and conversely mating ecology is likely to evolve in response to manipulation attempts. A better understanding of (female) mating behaviour will help anticipate and overcome potential challenges, and thus make desirable outcomes more likely.
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Affiliation(s)
- Andreas Sutter
- School of Biological Sciences, University of East Anglia, Norwich Research Park, NR4 7TJ Norwich, UK
| | - Tom Ar Price
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Nina Wedell
- Biosciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK.
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Suppression of female fertility in Aedes aegypti with a CRISPR-targeted male-sterile mutation. Proc Natl Acad Sci U S A 2021; 118:2105075118. [PMID: 34031258 DOI: 10.1073/pnas.2105075118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Aedes aegypti spread devastating viruses such as dengue, which causes disease among 100 to 400 million people annually. A potential approach to control mosquito disease vectors is the sterile insect technique (SIT). The strategy involves repeated release of large numbers of sterile males, which reduces insect populations because the sterile males mate and thereby suppress the fertility of females that would otherwise mate with fertile males. While SIT has been successful in suppressing certain agricultural pests, it has been less effective in depressing populations of Ae. aegypti This limitation is in part because of the fitness effects resulting from mutagenizing the mosquitoes nonspecifically. Here, we introduced and characterized the impact on female fertility of an Ae. aegypti mutation that disrupts a gene that is specifically expressed in testes. We used CRISPR/Cas9 to generate a null mutation in the Ae. aegypti β2-tubulin (B2t) gene, which eliminates male fertility. When we allowed wild-type females to first mate with B2t mutant males, most of the females did not produce progeny even after being subsequently exposed to wild-type males. We also introduced B2t mutant and wild-type males simultaneously with wild-type females and found that a larger number of B2t mutant males relative to the wild-type males was effective in significantly suppressing female fertility. These results raise the possibility of employing B2t sterile males to improve the efficacy of SIT in suppressing populations of Ae. aegypti through repeated releases and thereby reduce the transmission of viruses by these invasive mosquitoes.
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54
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Dalla Benetta E, Akbari OS, Ferree PM. Mechanistically comparing reproductive manipulations caused by selfish chromosomes and bacterial symbionts. Heredity (Edinb) 2021; 126:707-716. [PMID: 33649572 PMCID: PMC8102561 DOI: 10.1038/s41437-021-00410-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/18/2021] [Accepted: 01/18/2021] [Indexed: 01/30/2023] Open
Abstract
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.
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Affiliation(s)
- Elena Dalla Benetta
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA 91711 USA ,grid.266100.30000 0001 2107 4242Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, CA 92093 USA
| | - Omar S. Akbari
- grid.266100.30000 0001 2107 4242Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, 9500 Gilman Drive, CA 92093 USA
| | - Patrick M. Ferree
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA 91711 USA
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Abstract
CRISPR-Cas gene editing tools have brought us to an era of synthetic biology that will change the world. Excitement over the breakthroughs these tools have enabled in biology and medicine is balanced, justifiably, by concern over how their applications might go wrong in open environments. We do not know how genomic processes (including regulatory and epigenetic processes), evolutionary change, ecosystem interactions, and other higher order processes will affect traits, fitness, and impacts of edited organisms in nature. However, anticipating the spread, change, and impacts of edited traits or organisms in heterogeneous, changing environments is particularly important with "gene drives on the horizon." To anticipate how "synthetic threads" will affect the web of life on Earth, scientists must confront complex system interactions across many levels of biological organization. Currently, we lack plans, infrastructure, and funding for field science and scientists to track new synthetic organisms, with or without gene drives, as they move through open environments.
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Champer J, Champer SE, Kim IK, Clark AG, Messer PW. Design and analysis of CRISPR-based underdominance toxin-antidote gene drives. Evol Appl 2021; 14:1052-1069. [PMID: 33897820 PMCID: PMC8061266 DOI: 10.1111/eva.13180] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 12/24/2022] Open
Abstract
CRISPR gene drive systems offer a mechanism for transmitting a desirable transgene throughout a population for purposes ranging from vector-borne disease control to invasive species suppression. In this simulation study, we assess the performance of several CRISPR-based underdominance gene drive constructs employing toxin-antidote (TA) principles. These drives disrupt the wild-type version of an essential gene using a CRISPR nuclease (the toxin) while simultaneously carrying a recoded version of the gene (the antidote). Drives of this nature allow for releases that could be potentially confined to a desired geographic location. This is because such drives have a nonzero-invasion threshold frequency required for the drive to spread through the population. We model drives which target essential genes that are either haplosufficient or haplolethal, using nuclease promoters with expression restricted to the germline, promoters that additionally result in cleavage activity in the early embryo from maternal deposition, and promoters that have ubiquitous somatic expression. We also study several possible drive architectures, considering both "same-site" and "distant-site" systems, as well as several reciprocally targeting drives. Together, these drive variants provide a wide range of invasion threshold frequencies and options for both population modification and suppression. Our results suggest that CRISPR TA underdominance drive systems could allow for the design of flexible and potentially confinable gene drive strategies.
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Affiliation(s)
- Jackson Champer
- Department of Computational BiologyCornell UniversityIthacaNew YorkUSA
- Department of Molecular Biology and GeneticsCornell UniversityIthacaNew YorkUSA
| | - Samuel E. Champer
- Department of Computational BiologyCornell UniversityIthacaNew YorkUSA
| | - Isabel K. Kim
- Department of Computational BiologyCornell UniversityIthacaNew YorkUSA
| | - Andrew G. Clark
- Department of Computational BiologyCornell UniversityIthacaNew YorkUSA
- Department of Molecular Biology and GeneticsCornell UniversityIthacaNew YorkUSA
| | - Philipp W. Messer
- Department of Computational BiologyCornell UniversityIthacaNew YorkUSA
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Connolly JB, Mumford JD, Fuchs S, Turner G, Beech C, North AR, Burt A. Systematic identification of plausible pathways to potential harm via problem formulation for investigational releases of a population suppression gene drive to control the human malaria vector Anopheles gambiae in West Africa. Malar J 2021; 20:170. [PMID: 33781254 PMCID: PMC8006393 DOI: 10.1186/s12936-021-03674-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Population suppression gene drive has been proposed as a strategy for malaria vector control. A CRISPR-Cas9-based transgene homing at the doublesex locus (dsxFCRISPRh) has recently been shown to increase rapidly in frequency in, and suppress, caged laboratory populations of the malaria mosquito vector Anopheles gambiae. Here, problem formulation, an initial step in environmental risk assessment (ERA), was performed for simulated field releases of the dsxFCRISPRh transgene in West Africa. METHODS Building on consultative workshops in Africa that previously identified relevant environmental and health protection goals for ERA of gene drive in malaria vector control, 8 potentially harmful effects from these simulated releases were identified. These were stratified into 46 plausible pathways describing the causal chain of events that would be required for potential harms to occur. Risk hypotheses to interrogate critical steps in each pathway, and an analysis plan involving experiments, modelling and literature review to test each of those risk hypotheses, were developed. RESULTS Most potential harms involved increased human (n = 13) or animal (n = 13) disease transmission, emphasizing the importance to subsequent stages of ERA of data on vectorial capacity comparing transgenics to non-transgenics. Although some of the pathways (n = 14) were based on known anatomical alterations in dsxFCRISPRh homozygotes, many could also be applicable to field releases of a range of other transgenic strains of mosquito (n = 18). In addition to population suppression of target organisms being an accepted outcome for existing vector control programmes, these investigations also revealed that the efficacy of population suppression caused by the dsxFCRISPRh transgene should itself directly affect most pathways (n = 35). CONCLUSIONS Modelling will play an essential role in subsequent stages of ERA by clarifying the dynamics of this relationship between population suppression and reduction in exposure to specific potential harms. This analysis represents a comprehensive identification of plausible pathways to potential harm using problem formulation for a specific gene drive transgene and organism, and a transparent communication tool that could inform future regulatory studies, guide subsequent stages of ERA, and stimulate further, broader engagement on the use of population suppression gene drive to control malaria vectors in West Africa.
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Affiliation(s)
- John B Connolly
- Department of Life Sciences, Imperial College London, London, UK.
| | - John D Mumford
- Centre for Environmental Policy, Imperial College London, London, UK
| | - Silke Fuchs
- Department of Life Sciences, Imperial College London, London, UK
| | - Geoff Turner
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Ace R North
- Department of Zoology, University of Oxford, Oxford, UK
| | - Austin Burt
- Department of Life Sciences, Imperial College London, London, UK
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Tur C, Almenar D, Benlloch-Navarro S, Argilés-Herrero R, Zacarés M, Dalmau V, Pla I. Sterile Insect Technique in an Integrated Vector Management Program against Tiger Mosquito Aedes albopictus in the Valencia Region (Spain): Operating Procedures and Quality Control Parameters. INSECTS 2021; 12:272. [PMID: 33807092 PMCID: PMC8004901 DOI: 10.3390/insects12030272] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/25/2021] [Accepted: 03/16/2021] [Indexed: 12/22/2022]
Abstract
Aedes albopictus and Aedes aegypti are the main vectors of arboviral diseases such as dengue, Zika and chikungunya viruses. About a third of the world population is currently at risk of contracting Aedes-borne epidemics. In recent years, A. albopictus has drastically increased its distribution in many countries. In the absence of efficient mosquito vector control methods, the sterile insect technique (SIT) is presented as a very promising and environment-friendly control tool. The Agriculture Department of the Valencian Region is promoting an ongoing pilot project to evaluate the efficacy of an integrated vector management program (IVM) based on the use of the SIT as the main method of control. The laboratory studies for evaluating the entomological efficacy of SIT through the phased conditional testing process recommended by World Health Organization and the International Atomic Energy Agency (WHO-IAEA) are addressed. This study describes the routine operating procedures and quality control parameters for the medium-scale rearing of sterile male A. albopictus. More than 15 million sterile males have been produced and released in an area of 80 ha between 2018 and 2020. Of the initial L1 larvae, we recovered 17.2% of male pupae after sex sorting to be sterilized and released on the field, while the rest of the pupae remained available to maintain the rearing colony. The residual percentage of females after sex sorting was on average 0.17%. The obtained values in terms of production and quality control as well as the proposed rearing methodology can be useful for designing a medium-scale mosquito-rearing pipeline.
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Affiliation(s)
- Carlos Tur
- Empresa de Transformación Agraria S.A., S.M.E, M.P. (TRAGSA), Avenida de la Industria 26, 46980 Paterna, Spain; (D.A.); (S.B.-N.); (I.P.)
- Escuela de Doctorado, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain
| | - David Almenar
- Empresa de Transformación Agraria S.A., S.M.E, M.P. (TRAGSA), Avenida de la Industria 26, 46980 Paterna, Spain; (D.A.); (S.B.-N.); (I.P.)
| | - Sandra Benlloch-Navarro
- Empresa de Transformación Agraria S.A., S.M.E, M.P. (TRAGSA), Avenida de la Industria 26, 46980 Paterna, Spain; (D.A.); (S.B.-N.); (I.P.)
| | - Rafael Argilés-Herrero
- Insect Pest Control Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagramerstrasse 5, P.O. Box 100, A-1400 Vienna, Austria;
| | - Mario Zacarés
- Departamento de Ciencias Básicas y Transversales, Facultad de Veterinaria y Ciencias Experimentales, Universidad Católica de Valencia San Vicente Mártir, C/Guillem de Castro 94, 46001 Valencia, Spain;
| | - Vicente Dalmau
- Conselleria de Agricultura, Desarrollo Rural, Emergencia Climática y Transición Ecológica, Ctra Alicante-Valencia s/n Apdo correos 125, 46460 Silla, Spain;
| | - Ignacio Pla
- Empresa de Transformación Agraria S.A., S.M.E, M.P. (TRAGSA), Avenida de la Industria 26, 46980 Paterna, Spain; (D.A.); (S.B.-N.); (I.P.)
- Escuela de Doctorado, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain
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Hybrid mosquitoes? Evidence from rural Tanzania on how local communities conceptualize and respond to modified mosquitoes as a tool for malaria control. Malar J 2021; 20:134. [PMID: 33676493 PMCID: PMC7937266 DOI: 10.1186/s12936-021-03663-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/23/2021] [Indexed: 01/03/2023] Open
Abstract
Background Different forms of mosquito modifications are being considered as potential high-impact and low-cost tools for future malaria control in Africa. Although still under evaluation, the eventual success of these technologies will require high-level public acceptance. Understanding prevailing community perceptions of mosquito modification is, therefore, crucial for effective design and implementation of these interventions. This study investigated community perceptions regarding genetically-modified mosquitoes (GMMs) and their potential for malaria control in Tanzanian villages where no research or campaign for such technologies has yet been undertaken. Methods A mixed-methods design was used, involving: (i) focus group discussions (FGD) with community leaders to get insights on how they frame and would respond to GMMs, and (ii) structured questionnaires administered to 490 community members to assess awareness, perceptions and support for GMMs for malaria control. Descriptive statistics were used to summarize the findings and thematic content analysis was used to identify key concepts and interpret the findings. Results Nearly all survey respondents were unaware of mosquito modification technologies for malaria control (94.3%), and reported no knowledge of their specific characteristics (97.3%). However, community leaders participating in FGDs offered a set of distinctive interpretive frames to conceptualize interventions relying on GMMs for malaria control. The participants commonly referenced their experiences of cross-breeding for selecting preferred traits in domestic plants and animals. Preferred GMMs attributes included the expected reductions in insecticide use and human labour. Population suppression approaches, requiring as few releases as possible, were favoured. Common concerns included whether the GMMs would look or behave differently than wild mosquitoes, and how the technology would be integrated into current malaria control policies. The participants emphasised the importance and the challenge of educating and engaging communities during the technology development. Conclusions Understanding how communities perceive and interpret novel technologies is crucial to the design and effective implementation of new vector control programmes. This study offers vital clues on how communities with no prior experience of modified mosquitoes might conceptualize or respond to such technologies when deployed in the context of malaria control programmes. Drawing upon existing interpretive frames and locally-resonant analogies when deploying such technologies may provide a basis for more durable public support in the future.
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60
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Hosack GR, Ickowicz A, Hayes KR. Quantifying the risk of vector-borne disease transmission attributable to genetically modified vectors. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201525. [PMID: 33959322 PMCID: PMC8074930 DOI: 10.1098/rsos.201525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 02/11/2021] [Indexed: 06/12/2023]
Abstract
The relative risk of disease transmission caused by the potential release of transgenic vectors, such as through sterile insect technique or gene drive systems, is assessed with comparison with wild-type vectors. The probabilistic risk framework is demonstrated with an assessment of the relative risk of lymphatic filariasis, malaria and o'nyong'nyong arbovirus transmission by mosquito vectors to human hosts given a released transgenic strain of Anopheles coluzzii carrying a dominant sterile male gene construct. Harm is quantified by a logarithmic loss function that depends on the causal risk ratio, which is a quotient of basic reproduction numbers derived from mathematical models of disease transmission. The basic reproduction numbers are predicted to depend on the number of generations in an insectary colony and the number of backcrosses between the transgenic and wild-type lineages. Analogous causal risk ratios for short-term exposure to a single cohort release are also derived. These causal risk ratios were parametrized by probabilistic elicitations, and updated with experimental data for adult vector mortality. For the wild-type, high numbers of insectary generations were predicted to reduce the number of infectious human cases compared with uncolonized wild-type. Transgenic strains were predicted to produce fewer infectious cases compared with the uncolonized wild-type.
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Affiliation(s)
- Geoffrey R. Hosack
- Commonwealth Scientific and Industrial Research Organisation, Data61, Hobart, Tasmania, Australia
| | - Adrien Ickowicz
- Commonwealth Scientific and Industrial Research Organisation, Data61, Hobart, Tasmania, Australia
| | - Keith R. Hayes
- Commonwealth Scientific and Industrial Research Organisation, Data61, Hobart, Tasmania, Australia
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Grogan C, Bennett M, Moore S, Lampe D. Novel Asaia bogorensis Signal Sequences for Plasmodium Inhibition in Anopheles stephensi. Front Microbiol 2021; 12:633667. [PMID: 33664722 PMCID: PMC7921796 DOI: 10.3389/fmicb.2021.633667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/27/2021] [Indexed: 12/11/2022] Open
Abstract
Mosquitoes vector many pathogens that cause human disease, such as malaria that is caused by parasites in the genus Plasmodium. Current strategies to control vector-transmitted diseases are hindered by mosquito and pathogen resistance, so research has turned to altering the microbiota of the vectors. In this strategy, called paratransgenesis, symbiotic bacteria are genetically modified to affect the mosquito's phenotype by engineering them to deliver antiplasmodial effector molecules into the midgut to kill parasites. One paratransgenesis candidate is Asaia bogorensis, a Gram-negative, rod-shaped bacterium colonizing the midgut, ovaries, and salivary glands of Anopheles sp. mosquitoes. However, common secretion signals from E. coli and closely related species do not function in Asaia. Here, we report evaluation of 20 native Asaia N-terminal signal sequences predicted from bioinformatics for their ability to mediate increased levels of antiplasmodial effector molecules directed to the periplasm and ultimately outside the cell. We tested the hypothesis that by increasing the amount of antiplasmodials released from the cell we would also increase parasite killing power. We scanned the Asaia bogorensis SF2.1 genome to identify signal sequences from extra-cytoplasmic proteins and fused these to the reporter protein alkaline phosphatase. Six signals resulted in significant levels of protein released from the Asaia bacterium. Three signals were successfully used to drive the release of the antimicrobial peptide, scorpine. Further testing in mosquitoes demonstrated that these three Asaia strains were able to suppress the number of oocysts formed after a blood meal containing P. berghei to a significantly greater degree than wild-type Asaia, although prevalence was not decreased beyond levels obtained with a previously isolated siderophore receptor signal sequence. We interpret these results to indicate that there is a maximum level of suppression that can be achieved when the effectors are constitutively driven due to stress on the symbionts. This suggests that simply increasing the amount of antiplasmodial effector molecules in the midgut is insufficient to create superior paratransgenic bacterial strains and that symbiont fitness must be considered as well.
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Affiliation(s)
- Christina Grogan
- Department of Biological Sciences, Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, PA, United States
| | - Marissa Bennett
- Department of Biological Sciences, Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, PA, United States
| | - Shannon Moore
- Department of Biological Sciences, Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, PA, United States
| | - David Lampe
- Department of Biological Sciences, Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, PA, United States
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62
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Champer J, Kim IK, Champer SE, Clark AG, Messer PW. Suppression gene drive in continuous space can result in unstable persistence of both drive and wild-type alleles. Mol Ecol 2021; 30:1086-1101. [PMID: 33404162 DOI: 10.1111/mec.15788] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 12/23/2020] [Indexed: 12/31/2022]
Abstract
Rapid evolutionary processes can produce drastically different outcomes when studied in panmictic population models vs. spatial models. One such process is gene drive, which describes the spread of "selfish" genetic elements through a population. Engineered gene drives are being considered for the suppression of disease vectors or invasive species. While laboratory experiments and modelling in panmictic populations have shown that such drives can rapidly eliminate a population, it remains unclear if these results translate to natural environments where individuals inhabit a continuous landscape. Using spatially explicit simulations, we show that the release of a suppression drive can result in what we term "chasing" dynamics, in which wild-type individuals recolonize areas where the drive has locally eliminated the population. Despite the drive subsequently reconquering these areas, complete population suppression often fails to occur or is substantially delayed. This increases the likelihood that the drive is lost or that resistance evolves. We analyse how chasing dynamics are influenced by the type of drive, its efficiency, fitness costs, and ecological factors such as the maximal growth rate of the population and levels of dispersal and inbreeding. We find that chasing is more common for lower efficiency drives when dispersal is low and that some drive mechanisms are substantially more prone to chasing behaviour than others. Our results demonstrate that the population dynamics of suppression gene drives are determined by a complex interplay of genetic and ecological factors, highlighting the need for realistic spatial modelling to predict the outcome of drive releases in natural populations.
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Affiliation(s)
- Jackson Champer
- Department of Computational Biology, Cornell University, Ithaca, New York, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, USA
| | - Isabel K Kim
- Department of Computational Biology, Cornell University, Ithaca, New York, USA
| | - Samuel E Champer
- Department of Computational Biology, Cornell University, Ithaca, New York, USA
| | - Andrew G Clark
- Department of Computational Biology, Cornell University, Ithaca, New York, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, USA
| | - Philipp W Messer
- Department of Computational Biology, Cornell University, Ithaca, New York, USA
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63
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Shults P, Cohnstaedt LW, Adelman ZN, Brelsfoard C. Next-generation tools to control biting midge populations and reduce pathogen transmission. Parasit Vectors 2021; 14:31. [PMID: 33413518 PMCID: PMC7788963 DOI: 10.1186/s13071-020-04524-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/05/2020] [Indexed: 02/06/2023] Open
Abstract
Biting midges of the genus Culicoides transmit disease-causing agents resulting in a significant economic impact on livestock industries in many parts of the world. Localized control efforts, such as removal of larval habitat or pesticide application, can be logistically difficult, expensive and ineffective if not instituted and maintained properly. With these limitations, a population-level approach to the management of Culicoides midges should be investigated as a means to replace or supplement existing control strategies. Next-generation control methods such as Wolbachia- and genetic-based population suppression and replacement are being investigated in several vector species. Here we assess the feasibility and applicability of these approaches for use against biting midges. We also discuss the technical and logistical hurdles needing to be addressed for each method to be successful, as well as emphasize the importance of addressing community engagement and involving stakeholders in the investigation and development of these approaches.
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Affiliation(s)
- Phillip Shults
- Texas A&M University, 370 Olsen Blvd, College Station, TX, 77843, USA.
| | - Lee W Cohnstaedt
- USDA-ARS Arthropod Borne Animal Disease Research Unit, 1515 College Ave, Manhattan, KS, 66502, USA
| | - Zach N Adelman
- Texas A&M University, 370 Olsen Blvd, College Station, TX, 77843, USA
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Cator LJ, Wyer CAS, Harrington LC. Mosquito Sexual Selection and Reproductive Control Programs. Trends Parasitol 2021; 37:330-339. [PMID: 33422425 DOI: 10.1016/j.pt.2020.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/19/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022]
Abstract
The field of mosquito mating biology has experienced a considerable expansion in the past decade. Recent work has generated many key insights about specific aspects of mating behavior and physiology. Here, we synthesize these findings and classify swarming mosquito systems as polygynous. Male mating success is highly variable in swarms and evidence suggests that it is likely determined by both scramble competition between males and female choice. Incorporating this new understanding will improve both implementation and long-term stability of reproductive control tools.
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Affiliation(s)
- Lauren J Cator
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - Claudia A S Wyer
- Department of Life Sciences, Imperial College London, Ascot, UK; Science and Solutions for a Changing Planet DTP, Kensington, London SW7 2AZ, UK
| | - Laura C Harrington
- Department of Entomology, Cornell University, Ithaca, New York, NY, USA.
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femaleless Controls Sex Determination and Dosage Compensation Pathways in Females of Anopheles Mosquitoes. Curr Biol 2021; 31:1084-1091.e4. [PMID: 33417880 PMCID: PMC7955153 DOI: 10.1016/j.cub.2020.12.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/09/2020] [Accepted: 12/11/2020] [Indexed: 01/04/2023]
Abstract
The insect sex determination and the intimately linked dosage compensation pathways represent a challenging evolutionary puzzle that has been solved only in Drosophila melanogaster. Analyses of orthologs of the Drosophila genes identified in non-drosophilid taxa1,2 revealed that evolution of sex determination pathways is consistent with a bottom-up mode,3 where only the terminal genes within the pathway are well conserved. doublesex (dsx), occupying a bottom-most position and encoding sex-specific proteins orchestrating downstream sexual differentiation processes, is an ancient sex-determining gene present in all studied species.2,4,5 With the exception of lepidopterans, its female-specific splicing is known to be regulated by transformer (tra) and its co-factor transformer-2 (tra2).6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 Here we show that in the African malaria mosquito Anopheles gambiae, a gene, which likely arose in the Anopheles lineage and which we call femaleless (fle), controls sex determination in females by regulating splicing of dsx and fruitless (fru; another terminal gene within a branch of the sex determination pathway). Moreover, fle represents a novel molecular link between the sex determination and dosage compensation pathways. It is necessary to suppress activation of dosage compensation in females, as demonstrated by the significant upregulation of the female X chromosome genes and a correlated female-specific lethality, but no negative effect on males, in response to fle knockdown. This unexpected property, combined with a high level of conservation in sequence and function in anopheline mosquitoes, makes fle an excellent target for genetic control of all major vectors of human malaria. fle is a new sex determination pathway element conserved in Anopheles mosquitoes fle may have originated in the Anopheles lineage and is highly conserved in Anopheles fle suppresses activation of dosage compensation in females Depletion of fle transcripts is lethal or otherwise deleterious to females
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66
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Che LR, He ZB, Liu Y, Yan ZT, Han BZ, Chen XJ, He XF, Zhang JJ, Chen B, Qiao L. Electroporation-mediated nucleic acid delivery during non-embryonic stages for gene-function analysis in Anopheles sinensis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 128:103500. [PMID: 33278627 DOI: 10.1016/j.ibmb.2020.103500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
The delivery of exogenous nucleic acids to eggs or non-embryonic individuals by microinjection is a vital reverse genetics technique used to determine gene function in mosquitoes. However, DNA delivery to eggs is complex and time-consuming, and conventional, non-embryonic-injection techniques may result in unobvious phenotypes caused by insufficient absorption of nucleic acid fragments by cells at target body parts or tissues. In this study, we developed a set of electroporation-mediated non-embryonic microinjections for the delivery of exogenous nucleic acids in Anopheles sinensis. Gene silencing using this method led to down-regulation of target gene expression (AsCPR128) by 77% in targeted body parts, compared with only 10% in non-targeted body parts, thus increasing the defect-phenotype rate in the target area by 5.3-fold, compared with non-shock injected controls. Electroporation-mediated somatic transgenesis resulted in stable phenotypic characteristics of the reporter gene at the shocked body parts during the pupal-adult stages in about 69% of individuals. Furthermore, injecting plasmid DNA near the ovaries of female mosquitoes after a blood meal followed by electric shock produced three germline G1 transgenic lines, with a transformation rate of about 11.1% (calculated from ovulatory G0 females). Among the positive G1 lines, 42%, 40%, and 31% of individuals emitted red fluorescence in the larval stage. When the red fluorescent larvae developed into adults, green fluorescence was emitted from the ovaries of the females upon feeding. These results suggest that electroporation-mediated non-embryonic microinjection can be an efficient, rapid, and simple technique for analyzing gene function in non-model mosquitoes or other small insects.
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Affiliation(s)
- Lin-Rong Che
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Zheng-Bo He
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Yan Liu
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Zhen-Tian Yan
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Bao-Zhu Han
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Xiao-Jie Chen
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Xing-Fei He
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Jia-Jun Zhang
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Bin Chen
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China.
| | - Liang Qiao
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China.
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67
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Leftwich PT, Spurgin LG, Harvey-Samuel T, Thomas CJE, Paladino LC, Edgington MP, Alphey L. Genetic pest management and the background genetics of release strains. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190805. [PMID: 33357053 DOI: 10.1098/rstb.2019.0805] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Genetic pest management (GPM) methods involve releasing modified versions of a pest species to mate with wild pests in the target area. Proposed for a wide range of applications in public health, agriculture and conservation, most progress has been made with pest insects. Offspring of the released modified insects and wild pests carry the modification-which might be transgenes, artificially introduced Wolbachia or genetic damage from radiation, for example-but they also carry a complete haploid genome from their laboratory-reared parent, as well as one from their wild parent. Unless these F1 hybrids are completely unable to reproduce, further mating will lead to introgression of DNA sequences from the release strain into the wild population. We discuss issues around strain selection and the potential consequences of such introgression. We conclude that such introgression is probably harmless in almost all circumstances, and could, in theory, provide specific additional benefits to the release programme. We outline population monitoring approaches that could be used, going forward, to determine how background genetics may affect GPM. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'.
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Affiliation(s)
- Philip T Leftwich
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK
| | - Lewis G Spurgin
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK
| | | | | | | | | | - Luke Alphey
- Arthropod Genetics, The Pirbright Institute, Pirbright GU24 0NF, UK
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68
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Yan Y, Scott MJ. Building a transgenic sexing strain for genetic control of the Australian sheep blow fly Lucilia cuprina using two lethal effectors. BMC Genet 2020; 21:141. [PMID: 33339506 PMCID: PMC8348823 DOI: 10.1186/s12863-020-00947-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background The sterile insect technique (SIT) has been
successfully used in many pest management programs worldwide.
Some SIT programs release both sexes due to the lack of genetic
sexing strains or efficient sex separation methods but sterile
females are ineffective control agents. Transgenic sexing
strains (TSS) using the tetracycline-off control system have
been developed in a variety of insect pests, from which females
die by either of two commonly used lethal effectors:
overexpression of the transcription factor tetracycline transactivator (tTA)
or ectopic expression of a proapoptotic gene, such as head involution defective
(hid). The lethality from
tTA overexpression is thought to be due to “transcriptional
squelching”, while hid causes
lethality by induction of apoptosis. This study aims to create
and characterize a TSS of Lucilia
cuprina, which is a major pest of sheep, by
combining both lethal effectors in a single transgenic
strain. Results Here a stable TSS of L.
cuprina (DH6) that carries two lethal effectors
was successfully generated, by crossing FL3#2 which carries a
female-specific tTA overexpression cassette, with EF1#12 which
carries a tTA-regulated LshidAla2 cassette. Females with
one copy of the FL3#2 transgene are viable but up to 99.8% of
homozygous females die at the pupal stage when raised on diet
that lacks tetracycline. Additionally, the female lethality of
FL3#2 was partially repressed by supplying tetracycline to the
parental generation. With an additional LshidAla2 effector, the female
lethality of DH6 is 100% dominant and cannot be repressed by
maternal tetracycline. DH6 females die at the late-larval stage.
Several fitness parameters important for mass rearing such as
hatching rate, adult emergence and sex ratio were comparable to
those of the wild type strain. Conclusions Compared to the parental FL3#2 strain, the DH6
strain shows stronger female lethality and lethality occurs at
an earlier stage of development. The combination of two
tTA-dependent lethal effectors could improve strain stability
under mass rearing and could reduce the risk of resistance in
the field if fertile males are released. Our approach could be
easily adapted for other pest species for an efficient, safe and
sustainable genetic control program. Supplementary Information The online version contains supplementary material available
at 10.1186/s12863-020-00947-y.
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Affiliation(s)
- Ying Yan
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.,Department of Insect Biotechnology in Plant Protection, Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Winchesterstraße 2, 35394, Giessen, Germany
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
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O’Leary S, Adelman ZN. CRISPR/Cas9 knockout of female-biased genes AeAct-4 or myo-fem in Ae. aegypti results in a flightless phenotype in female, but not male mosquitoes. PLoS Negl Trop Dis 2020; 14:e0008971. [PMID: 33338046 PMCID: PMC7781531 DOI: 10.1371/journal.pntd.0008971] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 01/04/2021] [Accepted: 11/11/2020] [Indexed: 02/04/2023] Open
Abstract
Aedes aegypti is a vector of dengue, chikungunya, and Zika viruses. Current vector control strategies such as community engagement, source reduction, and insecticides have not been sufficient to prevent viral outbreaks. Thus, interest in novel strategies involving genetic engineering is growing. Female mosquitoes rely on flight to mate with males and obtain a bloodmeal from a host. We hypothesized that knockout of genes specifically expressed in female mosquitoes associated with the indirect flight muscles would result in a flightless female mosquito. Using CRISPR-Cas9 we generated loss-of-function mutations in several genes hypothesized to control flight in mosquitoes, including actin (AeAct-4) and myosin (myo-fem) genes expressed specifically in the female flight muscle. Genetic knockout of these genes resulted in 100% flightless females, with homozygous males able to fly, mate, and produce offspring, albeit at a reduced rate when compared to wild type males. Interestingly, we found that while AeAct-4 was haplosufficient, with most heterozygous individuals capable of flight, this was not the case for myo-fem, where about half of individuals carrying only one intact copy could not fly. These findings lay the groundwork for developing novel mechanisms of controlling Ae. aegypti populations, and our results suggest that this mechanism could be applicable to other vector species of mosquito.
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Affiliation(s)
- Sarah O’Leary
- Department of Entomology, Texas A&M University, College Station, Texas, United States of America
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America
| | - Zach N. Adelman
- Department of Entomology, Texas A&M University, College Station, Texas, United States of America
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America
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70
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Edgington MP, Harvey-Samuel T, Alphey L. Split drive killer-rescue provides a novel threshold-dependent gene drive. Sci Rep 2020; 10:20520. [PMID: 33239631 PMCID: PMC7689494 DOI: 10.1038/s41598-020-77544-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 11/12/2020] [Indexed: 12/20/2022] Open
Abstract
A wide range of gene drive mechanisms have been proposed that are predicted to increase in frequency within a population even when they are deleterious to individuals carrying them. This also allows associated desirable genetic material ("cargo genes") to increase in frequency. Gene drives have garnered much attention for their potential use against a range of globally important problems including vector borne disease, crop pests and invasive species. Here we propose a novel gene drive mechanism that could be engineered using a combination of toxin-antidote and CRISPR components, each of which are already being developed for other purposes. Population genetics mathematical models are developed here to demonstrate the threshold-dependent nature of the proposed system and its robustness to imperfect homing, incomplete penetrance of toxins and transgene fitness costs, each of which are of practical significance given that real-world components inevitably have such imperfections. We show that although end-joining repair mechanisms may cause the system to break down, under certain conditions, it should persist over time scales relevant for genetic control programs. The potential of such a system to provide localised population suppression via sex ratio distortion or female-specific lethality is also explored. Additionally, we investigate the effect on introduction thresholds of adding an extra CRISPR base element, showing that this may either increase or decrease dependent on parameter context.
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Affiliation(s)
| | - Tim Harvey-Samuel
- The Pirbright Institute, Ash Road, Woking, Surrey, Pirbright, GU24 0NF, UK
| | - Luke Alphey
- The Pirbright Institute, Ash Road, Woking, Surrey, Pirbright, GU24 0NF, UK
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71
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Kang DS, Cunningham JM, Lovin DD, Chadee DD, Severson DW. Mating Competitiveness of Transgenic Aedes aegypti (Diptera: Culicidae) Males Against Wild-Type Males Reared Under Simulated Field Conditions. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1775-1781. [PMID: 32556270 PMCID: PMC7899268 DOI: 10.1093/jme/tjaa111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Indexed: 05/07/2023]
Abstract
Efforts directed at genetic modification of mosquitoes for population control or replacement are highly dependent on the initial mating success of transgenic male mosquitoes following their release into natural populations. Adult mosquito phenotypes are influenced by the environmental conditions experienced as larvae. Semifield studies conducted to date have not taken that under consideration when testing male mating fitness, and have compared mating success of males reared under identical environmental conditions. We performed pairwise mating challenges between males from a genetically modified laboratory strain (BF2) versus males from a recent Trinidad field isolate of Aedes aegypti (L.), a major vector of multiple arboviruses. We utilized larval density and nutrition to simulate environmental stress experienced by the Trinidad males and females. Our results indicated that environmental stress during larval development negatively influenced the competitiveness and reproductive success of males from the Trinidad population when paired with optimum reared BF2 males. Small (0.027 m3) and large (0.216 m3) trials were conducted wherein stressed or optimum Trinidad males competed with optimum BF2 males for mating with stressed Trinidad females. When competing with stress reared Trinidad males, optimum reared BF2 males were predominant in matings with stress reared Trinidad females, and large proportions of these females mated with males of both strains. When competing with optimum reared Trinidad males, no difference in mating success was observed between them and BF2 males, and frequencies of multiple matings were low. Our results indicate that future mating competition studies should incorporate appropriate environmental conditions when designing mating fitness trials of genetically modified males.
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Affiliation(s)
- David S Kang
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
| | | | - Diane D Lovin
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
| | - Dave D Chadee
- Department of Life Sciences, University of the West Indies, Saint Augustine, Trinidad and Tobago
| | - David W Severson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN
- Department of Life Sciences, University of the West Indies, Saint Augustine, Trinidad and Tobago
- Corresponding author, e-mail:
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72
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Naegeli H, Bresson J, Dalmay T, Dewhurst IC, Epstein MM, Guerche P, Hejatko J, Moreno FJ, Mullins E, Nogué F, Rostoks N, Sánchez Serrano JJ, Savoini G, Veromann E, Veronesi F, Bonsall MB, Mumford J, Wimmer EA, Devos Y, Paraskevopoulos K, Firbank LG. Adequacy and sufficiency evaluation of existing EFSA guidelines for the molecular characterisation, environmental risk assessment and post-market environmental monitoring of genetically modified insects containing engineered gene drives. EFSA J 2020; 18:e06297. [PMID: 33209154 PMCID: PMC7658669 DOI: 10.2903/j.efsa.2020.6297] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Advances in molecular and synthetic biology are enabling the engineering of gene drives in insects for disease vector/pest control. Engineered gene drives (that bias their own inheritance) can be designed either to suppress interbreeding target populations or modify them with a new genotype. Depending on the engineered gene drive system, theoretically, a genetic modification of interest could spread through target populations and persist indefinitely, or be restricted in its spread or persistence. While research on engineered gene drives and their applications in insects is advancing at a fast pace, it will take several years for technological developments to move to practical applications for deliberate release into the environment. Some gene drive modified insects (GDMIs) have been tested experimentally in the laboratory, but none has been assessed in small-scale confined field trials or in open release trials as yet. There is concern that the deliberate release of GDMIs in the environment may have possible irreversible and unintended consequences. As a proactive measure, the European Food Safety Authority (EFSA) has been requested by the European Commission to review whether its previously published guidelines for the risk assessment of genetically modified animals (EFSA, 2012 and 2013), including insects (GMIs), are adequate and sufficient for GDMIs, primarily disease vectors, agricultural pests and invasive species, for deliberate release into the environment. Under this mandate, EFSA was not requested to develop risk assessment guidelines for GDMIs. In this Scientific Opinion, the Panel on Genetically Modified Organisms (GMO) concludes that EFSA's guidelines are adequate, but insufficient for the molecular characterisation (MC), environmental risk assessment (ERA) and post-market environmental monitoring (PMEM) of GDMIs. While the MC,ERA and PMEM of GDMIs can build on the existing risk assessment framework for GMIs that do not contain engineered gene drives, there are specific areas where further guidance is needed for GDMIs.
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73
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Dhole S, Lloyd AL, Gould F. Gene Drive Dynamics in Natural Populations: The Importance of Density Dependence, Space, and Sex. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2020; 51:505-531. [PMID: 34366722 PMCID: PMC8340601 DOI: 10.1146/annurev-ecolsys-031120-101013] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The spread of synthetic gene drives is often discussed in the context of panmictic populations connected by gene flow and described with simple deterministic models. Under such assumptions, an entire species could be altered by releasing a single individual carrying an invasive gene drive, such as a standard homing drive. While this remains a theoretical possibility, gene drive spread in natural populations is more complex and merits a more realistic assessment. The fate of any gene drive released in a population would be inextricably linked to the population's ecology. Given the uncertainty often involved in ecological assessment of natural populations, understanding the sensitivity of gene drive spread to important ecological factors is critical. Here we review how different forms of density dependence, spatial heterogeneity, and mating behaviors can impact the spread of self-sustaining gene drives. We highlight specific aspects of gene drive dynamics and the target populations that need further research.
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Affiliation(s)
- Sumit Dhole
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Alun L Lloyd
- Biomathematics Graduate Program and Department of Mathematics, North Carolina State University, Raleigh, North Carolina 27695-8213, USA
- Genetic Engineering and Society Center, North Carolina State University, Raleigh, North Carolina 27695-7565, USA
| | - Fred Gould
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695, USA
- Genetic Engineering and Society Center, North Carolina State University, Raleigh, North Carolina 27695-7565, USA
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74
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Brewer TR, Bonsall MB. Combining refuges with transgenic insect releases for the management of an insect pest with non-recessive resistance to Bt crops in agricultural landscapes. J Theor Biol 2020; 509:110514. [PMID: 33053395 DOI: 10.1016/j.jtbi.2020.110514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/01/2020] [Accepted: 10/05/2020] [Indexed: 02/02/2023]
Abstract
Reinforcing the high-dose/refuge strategy with releases of transgenic insects has been suggested as a method for simultaneously managing agricultural pest populations and resistance to transgenic crops. Theoretical and empirical studies have shown that these approaches can work when deployed against closed populations and the assumptions of the HDR strategy are met. However, field-evolved resistance is often linked to non-recessive resistance or refuge non-compliance, and pest management regimes are likely to take place at the landscape-level. It is therefore important to understand how effective such strategies are when resistance is non-recessive, and how they could be employed in agricultural landscapes. We developed a spatially-explicit model to investigate the efficacy of strategies combining refuges with transgenic insect releases to manage a pest with non-recessive resistance in agricultural landscapes. We compared two release strategies, area-wide releases and localised releases targeted at population hotspots, and analysed the effects of refuge and release parameters on population and resistance dynamics. Area-wide releases reliably achieved landscape-level pest eradication. Localised releases also eradicated the pest when low release thresholds were combined with high release ratios, and maintained the pest at low densities when insufficient to achieve extinction. Reinforcing refuges with localised releases also greatly enhanced the probability of resistance extinction. However, when resistance remained in the population, localised releases prevented resistance from reaching fixation rather than greatly delaying or reversing resistance evolution. Our work indicates that combining refuges with simple release policies is effective for landscape-level pest suppression when the HDR assumptions are violated, but more nuanced release strategies may be required to enhance the benefits to resistance management.
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Affiliation(s)
- Tom R Brewer
- Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Rd, Oxford OX1 3SZ, United Kingdom.
| | - Michael B Bonsall
- Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Rd, Oxford OX1 3SZ, United Kingdom; St. Peter's College, New Inn Hall Street, Oxford OX1 2DL, United Kingdom
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75
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Pollegioni P, North AR, Persampieri T, Bucci A, Minuz RL, Groneberg DA, Nolan T, Papathanos P, Crisanti A, Müller R. Detecting the population dynamics of an autosomal sex ratio distorter transgene in malaria vector mosquitoes. J Appl Ecol 2020; 57:2086-2096. [PMID: 33149368 PMCID: PMC7594489 DOI: 10.1111/1365-2664.13702] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 06/09/2020] [Indexed: 11/28/2022]
Abstract
The development of genetically modified (GM) mosquitoes and their subsequent field release offers innovative and cost-effective approaches to reduce mosquito-borne diseases, such as malaria. A sex-distorting autosomal transgene has been developed recently in G3 mosquitoes, a laboratory strain of the malaria vector Anopheles gambiae s.l. The transgene expresses an endonuclease called I-PpoI during spermatogenesis, which selectively cleaves the X chromosome to result in ~95% male progeny. Following the World Health Organization guidance framework for the testing of GM mosquitoes, we assessed the dynamics of this transgene in large cages using a joint experimental modelling approach.We performed a 4-month experiment in large, indoor cages to study the population genetics of the transgene. The cages were set up to mimic a simple tropical environment with a diurnal light-cycle, constant temperature and constant humidity. We allowed the generations to overlap to engender a stable age structure in the populations. We constructed a model to mimic the experiments, and used the experimental data to infer the key model parameters.We identified two fitness costs associated with the transgene. First, transgenic adult males have reduced fertility and, second, their female progeny have reduced pupal survival rates. Our results demonstrate that the transgene is likely to disappear in <3 years under our confined conditions. Model predictions suggest this will be true over a wide range of background population sizes and transgene introduction rates. Synthesis and applications. Our study is in line with the World Health Organization guidance recommendations in regard to the development and testing of GM mosquitoes. Since the transgenic sex ratio distorter strain (Ag(PMB)1) has been considered for genetic vector control of malaria, we recorded the dynamics of this transgene in indoor-large cage populations and modelled its post-release persistence under different scenarios. We provide a demonstration of the self-limiting nature of the transgene, and identified new fitness costs that will further reduce the longevity of the transgene after its release. Finally, our study has showcased an alternative and effective statistical method for characterizing the phenotypic expression of a transgene in an insect pest population.
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Affiliation(s)
- Paola Pollegioni
- Polo d'Innovazione di GenomicaGenetica e Biologia Società Consortile R.L.TerniItaly
- National Research CouncilResearch Institute on Terrestrial EcosystemsPoranoItaly
| | - Ace R. North
- Department of ZoologyUniversity of OxfordOxfordUK
| | - Tania Persampieri
- Polo d'Innovazione di GenomicaGenetica e Biologia Società Consortile R.L.TerniItaly
| | - Alessandro Bucci
- Polo d'Innovazione di GenomicaGenetica e Biologia Società Consortile R.L.TerniItaly
| | - Roxana L. Minuz
- Polo d'Innovazione di GenomicaGenetica e Biologia Società Consortile R.L.TerniItaly
| | - David Alexander Groneberg
- Institute of Occupational Medicine, Social Medicine and Environmental MedicineGoethe University Frankfurt am MainFrankfurt am MainGermany
| | - Tony Nolan
- Department of Life SciencesImperial College LondonLondonUK
- Liverpool School of Tropical MedicineLiverpoolUK
| | - Philippos‐Aris Papathanos
- Department of Experimental MedicineUniversity of PerugiaPerugiaItaly
- Faculty of Agriculture, Food and EnvironmentHebrew University of JerusalemJerusalemIsrael
| | | | - Ruth Müller
- Polo d'Innovazione di GenomicaGenetica e Biologia Società Consortile R.L.TerniItaly
- Institute of Occupational Medicine, Social Medicine and Environmental MedicineGoethe University Frankfurt am MainFrankfurt am MainGermany
- Unit Medical EntomologyDepartment of Biomedical SciencesInstitute of Tropical MedicineAntwerpBelgium
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76
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Champer J, Yang E, Lee E, Liu J, Clark AG, Messer PW. A CRISPR homing gene drive targeting a haplolethal gene removes resistance alleles and successfully spreads through a cage population. Proc Natl Acad Sci U S A 2020; 117:24377-24383. [PMID: 32929034 PMCID: PMC7533649 DOI: 10.1073/pnas.2004373117] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Engineered gene drives are being explored as a new strategy in the fight against vector-borne diseases due to their potential for rapidly spreading genetic modifications through a population. However, CRISPR-based homing gene drives proposed for this purpose have faced a major obstacle in the formation of resistance alleles that prevent Cas9 cleavage. Here, we present a homing drive in Drosophila melanogaster that reduces the prevalence of resistance alleles below detectable levels by targeting a haplolethal gene with two guide RNAs (gRNAs) while also providing a rescue allele. Resistance alleles that form by end-joining repair typically disrupt the haplolethal target gene and are thus removed from the population because individuals that carry them are nonviable. We demonstrate that our drive is highly efficient, with 91% of the progeny of drive heterozygotes inheriting the drive allele and with no functional resistance alleles observed in the remainder. In a large cage experiment, the drive allele successfully spread to all individuals within a few generations. These results show that a haplolethal homing drive can provide an effective tool for targeted genetic modification of entire populations.
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Affiliation(s)
- Jackson Champer
- Department of Computational Biology, Cornell University, Ithaca, NY 14853;
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Emily Yang
- Department of Computational Biology, Cornell University, Ithaca, NY 14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Esther Lee
- Department of Computational Biology, Cornell University, Ithaca, NY 14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Jingxian Liu
- Department of Computational Biology, Cornell University, Ithaca, NY 14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Andrew G Clark
- Department of Computational Biology, Cornell University, Ithaca, NY 14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Philipp W Messer
- Department of Computational Biology, Cornell University, Ithaca, NY 14853;
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77
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De La Vega SR, Smith DJ, Fritz JA, Lucchesi EF, Huang S. Gynandromorphic Specimens of Culex erythrothorax, Culex pipiens Complex, Culex tarsalis, and Culiseta incidens Collected in Northern San Joaquin Valley, California. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2020; 36:208-211. [PMID: 33600593 DOI: 10.2987/20-6943.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Gynandromorphic insects bear both male and female characteristics. In mosquitoes, gynandromorphy has been documented in multiple species and it can include many different combinations of sex-specific traits such as plumose or filiform antennae, short or elongated palpi, and male or female terminalia. Here we report 4 gynandromorphic specimens of Culex erythrothorax, Cx. pipiens complex, Cx. tarsalis, and Culiseta incidens collected in the Northern San Joaquin Valley of California. Each of the specimens exhibited heads with female characteristics of short palpi and filiform antennae while displaying fully developed external male terminalia including basistyles and dististyles. The potential implication of gynandromorphism in genetic control of mosquito vectors is discussed.
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78
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Edgington MP, Harvey‐Samuel T, Alphey L. Population-level multiplexing: A promising strategy to manage the evolution of resistance against gene drives targeting a neutral locus. Evol Appl 2020; 13:1939-1948. [PMID: 32908596 PMCID: PMC7463328 DOI: 10.1111/eva.12945] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/19/2020] [Accepted: 02/25/2020] [Indexed: 01/30/2023] Open
Abstract
CRISPR-based gene drives bias inheritance in their favour by inducing double-stranded breaks (DSBs) at wild-type homologous loci and using the drive transgene as a repair template-converting drive heterozygotes into homozygotes. Recent studies have shown that alternate end-joining repair mechanisms produce cut-resistant alleles that rapidly induce drive failure. Multiplexing-simultaneously targeting multiple sites at the wild-type locus-is commonly assumed to overcome this issue since resistance would need to develop at all target sites for the system to fail. This may work for some population suppression drives targeting essential (e.g. viability or fertility) genes if careful design can ensure cut-resistant alleles themselves have low fitness. However, here, models are used to demonstrate that this approach will be ineffective when targeting neutral loci. We then go on to compare the performance of four alternative population-level multiplexing approaches with standard individual-level multiplexing. Two of these approaches have mechanisms preventing them from becoming linked, thus avoiding multiple simultaneous DSBs and giving a large improvement. Releasing multiple unlinked drives gives a modest improvement, while releasing multiple drives that may become linked over time produces a decrease in performance under the conditions tested here. Based on performance and technical feasibility, we then take one approach forward for further investigation, demonstrating its robustness to different performance parameters and its potential for controlling very large target populations.
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79
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Pérez-Estigarribia PE, Bliman PA, Schaerer CE. A class of fast-slow models for adaptive resistance evolution. Theor Popul Biol 2020; 135:32-48. [PMID: 32791081 DOI: 10.1016/j.tpb.2020.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/25/2020] [Accepted: 07/29/2020] [Indexed: 11/28/2022]
Abstract
Resistance to insecticide is considered nowadays one of the major threats to insect control, as its occurrence reduces drastically the efficiency of chemical control campaigns, and may also perturb the application of other control methods, like biological and genetic control. In order to account for the emergence and spread of such phenomenon as an effect of exposition to larvicide and/or adulticide, we develop in this paper a general time-continuous population model with two life phases, subsequently simplified through slow manifold theory. The derived models present density-dependent recruitment and mortality rates in a non-conventional way. We show that in absence of selection, they evolve in compliance with Hardy-Weinberg law; while in presence of selection and in the dominant or codominant cases, convergence to the fittest genotype occurs. The proposed mathematical models should allow for the study of several issues of importance related to the use of insecticides and other adaptive phenomena.
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Affiliation(s)
| | - Pierre-Alexandre Bliman
- Sorbonne Université, Université Paris-Diderot SPC, Inria, CNRS, Laboratoire Jacques-Louis Lions, équipe Mamba, 75005 Paris, France.
| | - Christian E Schaerer
- Polytechnic School, National University of Asunción, P.O. Box 2111 SL, San Lorenzo, Paraguay.
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80
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North AR, Burt A, Godfray HCJ. Modelling the suppression of a malaria vector using a CRISPR-Cas9 gene drive to reduce female fertility. BMC Biol 2020; 18:98. [PMID: 32782000 PMCID: PMC7422583 DOI: 10.1186/s12915-020-00834-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/22/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Gene drives based on CRISPR-Cas9 technology are increasingly being considered as tools for reducing the capacity of mosquito populations to transmit malaria, and one of the most promising options is driving endonuclease genes that reduce the fertility of female mosquitoes. In particular, there is much interest in constructs that target the conserved mosquito doublesex (dsx) gene such that the emergence of functional drive-resistant alleles is unlikely. Proof of principle that these constructs can lead to substantial population suppression has been obtained in population cages, and they are being evaluated for use in sub-Saharan Africa. Here, we use simulation modelling to understand the factors affecting the spread of this type of gene drive over a one million-square kilometre area of West Africa containing substantial environmental and social heterogeneity. RESULTS We found that a driving endonuclease gene targeting female fertility could lead to substantial reductions in malaria vector populations on a regional scale. The exact level of suppression is influenced by additional fitness costs of the transgene such as the somatic expression of Cas9, and its deposition in sperm or eggs leading to damage to the zygote. In the absence of these costs, or of emergent drive-resistant alleles that restore female fertility, population suppression across the study area is predicted to stabilise at ~ 95% 4 years after releases commence. Small additional fitness costs do not greatly affect levels of suppression, though if the fertility of females whose offspring transmit the construct drops by more than ~ 40%, then population suppression is much less efficient. We show the suppression potential of a drive allele with high fitness costs can be enhanced by engineering it also to express male bias in the progeny of transgenic males. Irrespective of the strength of the drive allele, the spatial model predicts somewhat less suppression than equivalent non-spatial models, in particular in highly seasonal regions where dry season stochasticity reduces drive efficiency. We explored the robustness of these results to uncertainties in mosquito ecology, in particular their method of surviving the dry season and their dispersal rates. CONCLUSIONS The modelling presented here indicates that considerable suppression of vector populations can be achieved within a few years of using a female sterility gene drive, though the impact is likely to be heterogeneous in space and time.
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Affiliation(s)
- Ace R North
- Department of Zoology, University of Oxford, Oxford, UK.
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81
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Scott MJ, Benoit JB, Davis RJ, Bailey ST, Varga V, Martinson EO, Hickner PV, Syed Z, Cardoso GA, Torres TT, Weirauch MT, Scholl EH, Phillippy AM, Sagel A, Vasquez M, Quintero G, Skoda SR. Genomic analyses of a livestock pest, the New World screwworm, find potential targets for genetic control programs. Commun Biol 2020; 3:424. [PMID: 32753684 PMCID: PMC7403345 DOI: 10.1038/s42003-020-01152-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 07/14/2020] [Indexed: 12/13/2022] Open
Abstract
The New World Screwworm fly, Cochliomyia hominivorax, is a major pest of livestock in South America and Caribbean. However, few genomic resources have been available for this species. A genome of 534 Mb was assembled from long read PacBio DNA sequencing of DNA from a highly inbred strain. Analysis of molecular evolution identified 40 genes that are likely under positive selection. Developmental RNA-seq analysis identified specific genes associated with each stage. We identify and analyze the expression of genes that are likely important for host-seeking behavior (chemosensory), development of larvae in open wounds in warm-blooded animals (heat shock protein, immune response) and for building transgenic strains for genetic control programs including gene drive (sex determination, germline). This study will underpin future experiments aimed at understanding the parasitic lifestyle of the screwworm fly and greatly facilitate future development of strains for efficient systems for genetic control of screwworm.
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Affiliation(s)
- Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, McMicken School of Arts and Sciences, Cincinnati, OH, 45221, USA
| | - Rebecca J Davis
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA
| | - Samuel T Bailey
- Department of Biological Sciences, University of Cincinnati, McMicken School of Arts and Sciences, Cincinnati, OH, 45221, USA
| | - Virag Varga
- Department of Biological Sciences, University of Cincinnati, McMicken School of Arts and Sciences, Cincinnati, OH, 45221, USA
| | - Ellen O Martinson
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Paul V Hickner
- Department of Entomology, University of Kentucky, Lexington, KY, 40546, USA
| | | | - Gisele A Cardoso
- Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, Brazil
| | - Tatiana T Torres
- Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, Brazil
| | - Matthew T Weirauch
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
- Divisions of Biomedical Informatics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Elizabeth H Scholl
- Bioinformatics Research Center, North Carolina State University, Campus Box 7566, Raleigh, NC, 27695-7566, USA
| | - Adam M Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD, 20892, USA
| | | | | | | | - Steven R Skoda
- USDA-ARS, Tick and Biting Fly Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA
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82
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Qasim M, Xiao H, He K, Omar MAA, Liu F, Ahmed S, Li F. Genetic engineering and bacterial pathogenesis against the vectorial capacity of mosquitoes. Microb Pathog 2020; 147:104391. [PMID: 32679245 DOI: 10.1016/j.micpath.2020.104391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/05/2020] [Accepted: 07/09/2020] [Indexed: 12/19/2022]
Abstract
Mosquitoes are the main vector of multiple diseases worldwide and transmit viral (malaria, chikungunya, encephalitis, yellow fever, as well as dengue fever), as well as bacterial diseases (tularemia). To manage the outbreak of mosquito populations, various management programs include the application of chemicals, followed by biological and genetic control. Here we aimed to focus on the role of bacterial pathogenesis and molecular tactics for the management of mosquitoes and their vectorial capacity. Bacterial pathogenesis and molecular manipulations have a substantial impact on the biology of mosquitoes, and both strategies change the gene expression and regulation of disease vectors. The strategy for genetic modification is also proved to be excellent for the management of mosquitoes, which halt the development of population via incompatibility of different sex. Therefore, the purpose of the present discussion is to illustrate the impact of both approaches against the vectorial capacity of mosquitoes. Moreover, it could be helpful to understand the relationship of insect-pathogen and to manage various insect vectors as well as diseases.
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Affiliation(s)
- Muhammad Qasim
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China.
| | - Huamei Xiao
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China; College of Life Sciences and Resource Environment, Key Laboratory of Crop Growth and Development Regulation of Jiangxi Province, Yichun University, Yichun, 336000, China
| | - Kang He
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Mohamed A A Omar
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Feiling Liu
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Sohail Ahmed
- Department of Entomology, University of Agriculture, Faisalabad, 38040, Pakistan
| | - Fei Li
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China.
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83
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Bouyer J, Culbert NJ, Dicko AH, Pacheco MG, Virginio J, Pedrosa MC, Garziera L, Pinto ATM, Klaptocz A, Germann J, Wallner T, Salvador-Herranz G, Herrero RA, Yamada H, Balestrino F, Vreysen MJB. Field performance of sterile male mosquitoes released from an uncrewed aerial vehicle. Sci Robot 2020; 5:5/43/eaba6251. [DOI: 10.1126/scirobotics.aba6251] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/22/2020] [Indexed: 11/02/2022]
Abstract
Genetic control methods of mosquito vectors of malaria, dengue, yellow fever, and Zika are becoming increasingly popular due to the limitations of other techniques such as the use of insecticides. The sterile insect technique is an effective genetic control method to manage insect populations. However, it is crucial to release sterile mosquitoes by air to ensure homogeneous coverage, especially in large areas. Here, we report a fully automated adult mosquito release system operated from an uncrewed aerial vehicle or drone. Our system, developed and tested in Brazil, enabled a homogeneous dispersal of sterile male Aedes aegypti while maintaining their quality, leading to a homogeneous sterile-to-wild male ratio due to their aggregation in the same sites. Our results indicate that the released sterile males were able to compete with the wild males in mating with the wild females; thus, the sterile males were able to induce sterility in the native female population. The use of drones to implement the sterile insect technique will lead to improvements in areal coverage and savings in operational costs due to the requirement of fewer release sites and field staff.
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Affiliation(s)
- J. Bouyer
- Unité Mixte de Recherche ASTRE, CIRAD, INRA, Univ Montpellier, Montpellier, France
| | - N. J. Culbert
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, A-1400 Vienna, Austria
- Institute of Integrative Biology and the Centre for Genomic Research, University of Liverpool, Liverpool, Merseyside, UK
| | - A. H. Dicko
- WeRobotics, Rue d’Italie 11, 1204 Geneva, Switzerland
- Statistics for Development–STATS4D, Sacre Coeur III, 1 bis, P.O 11000, Dakar, Senegal
| | - M. Gomez Pacheco
- Biofábrica Moscamed Brasil, Av. C1, 992 - Quadra D 13, Lote 15, Distrito Industrial do São Francisco, Bahia, Brazil
| | - J. Virginio
- Biofábrica Moscamed Brasil, Av. C1, 992 - Quadra D 13, Lote 15, Distrito Industrial do São Francisco, Bahia, Brazil
| | - M. C. Pedrosa
- Biofábrica Moscamed Brasil, Av. C1, 992 - Quadra D 13, Lote 15, Distrito Industrial do São Francisco, Bahia, Brazil
| | - L. Garziera
- Biofábrica Moscamed Brasil, Av. C1, 992 - Quadra D 13, Lote 15, Distrito Industrial do São Francisco, Bahia, Brazil
| | - A. T. Macedo Pinto
- Biofábrica Moscamed Brasil, Av. C1, 992 - Quadra D 13, Lote 15, Distrito Industrial do São Francisco, Bahia, Brazil
| | - A. Klaptocz
- WeRobotics, Rue d’Italie 11, 1204 Geneva, Switzerland
| | - J. Germann
- WeRobotics, Rue d’Italie 11, 1204 Geneva, Switzerland
| | - T. Wallner
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, A-1400 Vienna, Austria
- WeRobotics, Rue d’Italie 11, 1204 Geneva, Switzerland
| | - G. Salvador-Herranz
- WeRobotics, Rue d’Italie 11, 1204 Geneva, Switzerland
- Instituto de Investigación e Innovación en Bioingeniería (I3B), Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain
| | - R. Argiles Herrero
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, A-1400 Vienna, Austria
| | - H. Yamada
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, A-1400 Vienna, Austria
| | - F. Balestrino
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, A-1400 Vienna, Austria
- Centro Agricoltura Ambiente “Giorgio Nicoli” S.r.l. (CAA), Via Sant’Agata, 835, 40014 Crevalcore BO, Italy
| | - M. J. B. Vreysen
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, A-1400 Vienna, Austria
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84
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Sougoufara S, Ottih EC, Tripet F. The need for new vector control approaches targeting outdoor biting Anopheline malaria vector communities. Parasit Vectors 2020; 13:295. [PMID: 32522290 PMCID: PMC7285743 DOI: 10.1186/s13071-020-04170-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022] Open
Abstract
Since the implementation of Roll Back Malaria, the widespread use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) is thought to have played a major part in the decrease in mortality and morbidity achieved in malaria-endemic regions. In the past decade, resistance to major classes of insecticides recommended for public health has spread across many malaria vector populations. Increasingly, malaria vectors are also showing changes in vector behaviour in response to current indoor chemical vector control interventions. Changes in the time of biting and proportion of indoor biting of major vectors, as well as changes in the species composition of mosquito communities threaten the progress made to control malaria transmission. Outdoor biting mosquito populations contribute to malaria transmission in many parts of sub-Saharan Africa and pose new challenges as they cannot be reliably monitored or controlled using conventional tools. Here, we review existing and novel approaches that may be used to target outdoor communities of malaria vectors. We conclude that scalable tools designed specifically for the control and monitoring of outdoor biting and resting malaria vectors with increasingly complex and dynamic responses to intensifying malaria control interventions are urgently needed. These are crucial for integrated vector management programmes designed to challenge current and future vector populations.
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Affiliation(s)
- Seynabou Sougoufara
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Emmanuel Chinweuba Ottih
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Frederic Tripet
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
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85
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Barry N, Toé P, Pare Toe L, Lezaun J, Drabo M, Dabiré RK, Diabate A. Motivations and expectations driving community participation in entomological research projects: Target Malaria as a case study in Bana, Western Burkina Faso. Malar J 2020; 19:199. [PMID: 32503546 PMCID: PMC7275576 DOI: 10.1186/s12936-020-03277-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/29/2020] [Indexed: 01/07/2023] Open
Abstract
Background Most field entomology research projects require active participation by local community members. Since 2012, Target Malaria, a not-for-profit research consortium, has been working with residents in the village of Bana, in Western Burkina Faso, in various studies involving mosquito collections, releases and recaptures. The long-term goal of this work is to develop innovative solutions to combat malaria in Africa with the help of mosquito modification technologies. Since the start of the project, Bana residents have played an important role in research activities, yet the motivations and expectations that drive their participation remain under-investigated. This study examines the factors that motivate some members of the local community to contribute to the implementation of Target Malaria’s activities, and, more broadly, explores the reasons that animate citizen participation in entomological research work in malaria-endemic regions. Methods A qualitative approach was used to survey the factors motivating members of the local community to assist in the implementation of Target Malaria’s entomological research activities in Bana. Eighty-five individual in-depth and semi-structured interviews were conducted, followed by three focus groups, one with youths who had participated in mosquito collections, and two with adult men and women from the village. All data collected were fully transcribed, processed, and subjected to thematic content analysis. Results Data showed that the willingness of local community members to participate in entomological research activities was informed by a wide range of motivational factors. Although interviewees expressed their motivations under different semantic registers, the data showed a degree of consistency around five categories of motivation: (a) enhance domestic protection from mosquitoes and malaria, (b) contribute to a future world free of the disease, (c) acquire knowledge and skills, (d) earn financial compensation, and (e) gain social prestige for the village. Conclusion These varying motivations reflect a set of differing personal and collective perceptions about the participation process, combining short and long-term, individual and collective motivations. Beyond the specific circumstances of this case, the study highlights the complex reasons that drive collective participation in entomological research and vector control activities. Detailed knowledge of community expectations should underpin any effort to mobilize local participation in field research activities.
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Affiliation(s)
- Nourou Barry
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso. .,Université Nazi BONI, Bobo-Dioulasso, Burkina Faso.
| | - Patrice Toé
- Université Nazi BONI, Bobo-Dioulasso, Burkina Faso
| | - Lea Pare Toe
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Javier Lezaun
- Institute for Science, Innovation and Society, School of Anthropology and Museum Ethnography, University of Oxford, Oxford, UK
| | - Mouhamed Drabo
- Department of Life Sciences, Imperial College of London, London, UK
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
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86
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Teem JL, Alphey L, Descamps S, Edgington MP, Edwards O, Gemmell N, Harvey-Samuel T, Melnick RL, Oh KP, Piaggio AJ, Saah JR, Schill D, Thomas P, Smith T, Roberts A. Genetic Biocontrol for Invasive Species. Front Bioeng Biotechnol 2020; 8:452. [PMID: 32523938 PMCID: PMC7261935 DOI: 10.3389/fbioe.2020.00452] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 04/20/2020] [Indexed: 12/11/2022] Open
Abstract
Invasive species are increasingly affecting agriculture, food, fisheries, and forestry resources throughout the world. As a result of global trade, invasive species are often introduced into new environments where they become established and cause harm to human health, agriculture, and the environment. Prevention of new introductions is a high priority for addressing the harm caused by invasive species, but unfortunately efforts to prevent new introductions do not address the economic harm that is presently manifested where invasive species have already become established. Genetic biocontrol can be defined as the release of organisms with genetic methods designed to disrupt the reproduction of invasive populations. While these methods offer the potential to control or even eradicate invasive species, there is a need to ensure that genetic biocontrol methods can be deployed in a way that minimizes potential harm to the environment. This review provides an overview of the state of genetic biocontrol, focusing on several approaches that were the subject of presentations at the Genetic Biocontrol for Invasive Species Workshop in Tarragona, Spain, March 31st, 2019, a workshop sponsored by the OECD’s Co-operative Research Program on Biological Resource Management for Sustainable Agricultural Systems. The review considers four different approaches to genetic biocontrol for invasive species; sterile-release, YY Males, Trojan Female Technique, and gene drive. The different approaches will be compared with respect to the efficiency each affords as a genetic biocontrol tool, the practical utility and cost/benefits associated with implementation of the approach, and the regulatory considerations that will need to be addressed for each. The opinions expressed and arguments employed in this publication are the sole responsibility of the authors and do not necessarily reflect those of the OECD or of the governments of its Member countries.
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Affiliation(s)
- John L Teem
- ILSI Research Foundation, Washington, DC, United States
| | - Luke Alphey
- The Pirbright Institute, Woking, United Kingdom
| | - Sarah Descamps
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | | | - Owain Edwards
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Wembley, WA, Australia
| | - Neil Gemmell
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | | | | | - Kevin P Oh
- National Wildlife Research Center, USDA/APHIS-Wildlife Services, Fort Collins, CO, United States
| | - Antoinette J Piaggio
- National Wildlife Research Center, USDA/APHIS-Wildlife Services, Fort Collins, CO, United States
| | | | - Dan Schill
- Fisheries Management Solutions, Inc., Boise, ID, United States
| | - Paul Thomas
- School of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - Trevor Smith
- Florida Department of Agriculture and Consumer Services, Gainesville, FL, United States
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87
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Champer J, Zhao J, Champer SE, Liu J, Messer PW. Population Dynamics of Underdominance Gene Drive Systems in Continuous Space. ACS Synth Biol 2020; 9:779-792. [PMID: 32142612 DOI: 10.1021/acssynbio.9b00452] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Underdominance systems can quickly spread through a population, but only when introduced in considerable numbers. This promises a gene drive mechanism that is less invasive than homing drives, potentially enabling new approaches in the fight against vector-borne diseases. If regional confinement can indeed be achieved, the decision-making process for a release would likely be much simpler compared to other, more invasive types of drives. The capacity of underdominance gene drive systems to spread in a target population without invading other populations is typically assessed via network models of panmictic demes linked by migration. However, it remains less clear how such systems would behave in more realistic population models where organisms move over a continuous landscape. Here, we use individual-based simulations to study the dynamics of several proposed underdominance systems in continuous-space. We find that all these systems can fail to persist in such environments, even after an initially successful establishment in the release area, confirming previous theoretical results from diffusion theory. At the same time, we find that a two-locus two-toxin-antidote system can invade connected demes through a narrow migration corridor. This suggests that the parameter space where underdominance systems can establish and persist in a release area while at the same time remaining confined to that area could be quite limited, depending on how a population is spatially structured. Overall, these results indicate that realistic spatial context must be considered when assessing strategies for the deployment of underdominance drives.
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88
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Webster SH, Vella MR, Scott MJ. Development and testing of a novel killer-rescue self-limiting gene drive system in Drosophila melanogaster. Proc Biol Sci 2020; 287:20192994. [PMID: 32292114 DOI: 10.1098/rspb.2019.2994] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Here we report the development and testing of a novel self-limiting gene drive system, Killer-Rescue (K-R), in Drosophila melanogaster. This system is composed of an autoregulated Gal4 Killer (K) and a Gal4-activated Gal80 Rescue (R). Overexpression of Gal4 is lethal, but in the presence of R activation of Gal80 leads to much lower levels of Gal4 and rescue of lethality. We demonstrate that with a single 2 : 1 engineered to wild-type release, K drives R through the population and after nine generations, more than 98% of the population carry R and less than 2% of the population are wild-type flies. We discuss how this simple K-R gene drive system may be readily adapted for population replacement in a human health pest, Aedes aegypti, or for population suppression in an agricultural pest, Drosophila suzukii.
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Affiliation(s)
- Sophia H Webster
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27615, USA
| | - Michael R Vella
- Biomathematics Graduate Program, North Carolina State University, Raleigh, NC 27615, USA
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27615, USA
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89
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McFarlane M, Almire F, Kean J, Donald CL, McDonald A, Wee B, Lauréti M, Varjak M, Terry S, Vazeille M, Gestuveo RJ, Dietrich I, Loney C, Failloux AB, Schnettler E, Pondeville E, Kohl A. The Aedes aegypti Domino Ortholog p400 Regulates Antiviral Exogenous Small Interfering RNA Pathway Activity and ago-2 Expression. mSphere 2020; 5:e00081-20. [PMID: 32269152 PMCID: PMC7142294 DOI: 10.1128/msphere.00081-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/13/2020] [Indexed: 02/03/2023] Open
Abstract
Arboviruses are pathogens of humans and animals. A better understanding of the interactions between these pathogens and the arthropod vectors, such as mosquitoes, that transmit them is necessary to develop novel control measures. A major antiviral pathway in the mosquito vector is the exogenous small interfering RNA (exo-siRNA) pathway, which is induced by arbovirus-derived double-stranded RNA in infected cells. Although recent work has shown the key role played by Argonaute-2 (Ago-2) and Dicer-2 (Dcr-2) in this pathway, the regulatory mechanisms that govern these pathways have not been studied in mosquitoes. Here, we show that the Domino ortholog p400 has antiviral activity against the alphavirus Semliki Forest virus (Togaviridae) both in Aedes aegypti-derived cells and in vivo Antiviral activity of p400 was also demonstrated against chikungunya virus (Togaviridae) and Bunyamwera virus (Peribunyaviridae) but not Zika virus (Flaviviridae). p400 was found to be expressed across mosquito tissues and regulated ago-2 but not dcr-2 transcript levels in A. aegypti mosquitoes. These findings provide novel insights into the regulation of an important aedine exo-siRNA pathway effector protein, Ago-2, by the Domino ortholog p400. They add functional insights to previous observations of this protein's antiviral and RNA interference regulatory activities in Drosophila melanogasterIMPORTANCE Female Aedes aegypti mosquitoes are vectors of human-infecting arthropod-borne viruses (arboviruses). In recent decades, the incidence of arthropod-borne viral infections has grown dramatically. Vector competence is influenced by many factors, including the mosquito's antiviral defenses. The exogenous small interfering RNA (siRNA) pathway is a major antiviral response restricting arboviruses in mosquitoes. While the roles of the effectors of this pathway, Argonaute-2 and Dicer-2 are well characterized, nothing is known about its regulation in mosquitoes. In this study, we demonstrate that A. aegypti p400, whose ortholog Domino in Drosophila melanogaster is a chromatin-remodeling ATPase member of the Tip60 complex, regulates siRNA pathway activity and controls ago-2 expression levels. In addition, we found p400 to have antiviral activity against different arboviruses. Therefore, our study provides new insights into the regulation of the antiviral response in A. aegypti mosquitoes.
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Affiliation(s)
- Melanie McFarlane
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Floriane Almire
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Joy Kean
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Claire L Donald
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Alma McDonald
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Bryan Wee
- Usher Institute for Population Health Sciences & Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | - Mathilde Lauréti
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Margus Varjak
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Sandra Terry
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Marie Vazeille
- Arboviruses and Insect Vectors Unit, Department of Virology, Institut Pasteur, Paris, France
| | - Rommel J Gestuveo
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
- Division of Biological Sciences, University of the Philippines Visayas, Miagao, Philippines
| | - Isabelle Dietrich
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Colin Loney
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Anna-Bella Failloux
- Arboviruses and Insect Vectors Unit, Department of Virology, Institut Pasteur, Paris, France
| | - Esther Schnettler
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Emilie Pondeville
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
| | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland
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Xu X, Bi H, Wang Y, Li X, Xu J, Liu Z, He L, Li K, Huang Y. Disruption of the ovarian serine protease (Osp) gene causes female sterility in Bombyx mori and Spodoptera litura. PEST MANAGEMENT SCIENCE 2020; 76:1245-1255. [PMID: 31595658 DOI: 10.1002/ps.5634] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/13/2019] [Accepted: 07/09/2018] [Indexed: 06/10/2023]
Abstract
BACKGROUND Precise regulation of oogenesis is crucial to female reproduction. Seventy percent of pests belong to lepidopteran species, so it would be interesting to explore the highly conserved genes involved in oogenesis that do not affect growth and development in the lepidopteran model, Bombyx mori. This can provide potential target genes for pest control and promote the development of insect sterility technology. RESULTS In lepidopteran species, ovarian serine protease (Osp), which encodes a member of the serine protease family, is essential for oogenesis. In this study, we used transgenic CRISPR/Cas9 technology to obtain Osp mutants in the model lepidopteran insect Bombyx mori and in the lepidopteran agricultural pest Spodoptera litura. Sequence analysis of mutants revealed an array of deletions in Osp loci in both species. We found that the deletion of Osp resulted in female sterility, whereas male fertility was not affected. Although B. mori and S. litura mutant females mated normally, they laid fewer eggs than wild-type females and eggs did not hatch. CONCLUSION Osp is crucial for female reproductive success in two species of Lepidoptera. As the Osp gene is highly conserved in insect species, this gene is a potential molecular target for genetic-based pest management. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Xia Xu
- School of Life Science, East China Normal University, Shanghai, China
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Honglun Bi
- School of Life Science, East China Normal University, Shanghai, China
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yaohui Wang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Xiaowei Li
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jun Xu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Zulian Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Lin He
- School of Life Science, East China Normal University, Shanghai, China
| | - Kai Li
- School of Life Science, East China Normal University, Shanghai, China
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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91
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Champer J, Kim IK, Champer SE, Clark AG, Messer PW. Performance analysis of novel toxin-antidote CRISPR gene drive systems. BMC Biol 2020; 18:27. [PMID: 32164660 PMCID: PMC7068947 DOI: 10.1186/s12915-020-0761-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/28/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND CRISPR gene drive systems allow the rapid spread of a genetic construct throughout a population. Such systems promise novel strategies for the management of vector-borne diseases and invasive species by suppressing a target population or modifying it with a desired trait. However, current homing-type drives have two potential shortcomings. First, they can be thwarted by the rapid evolution of resistance. Second, they lack any mechanism for confinement to a specific target population. In this study, we conduct a comprehensive performance assessment of several new types of CRISPR-based gene drive systems employing toxin-antidote (TA) principles, which should be less prone to resistance and allow for the confinement of drives to a target population due to invasion frequency thresholds. RESULTS The underlying principle of the proposed CRISPR toxin-antidote gene drives is to disrupt an essential target gene while also providing rescue by a recoded version of the target as part of the drive allele. Thus, drive alleles tend to remain viable, while wild-type targets are disrupted and often rendered nonviable, thereby increasing the relative frequency of the drive allele. Using individual-based simulations, we show that Toxin-Antidote Recessive Embryo (TARE) drives targeting an haplosufficient but essential gene (lethal when both copies are disrupted) can enable the design of robust, regionally confined population modification strategies with high flexibility in choosing promoters and targets. Toxin-Antidote Dominant Embryo (TADE) drives require a haplolethal target gene and a germline-restricted promoter, but they could permit faster regional population modification and even regionally confined population suppression. Toxin-Antidote Dominant Sperm (TADS) drives can be used for population modification or suppression. These drives are expected to spread rapidly and could employ a variety of promoters, but unlike TARE and TADE, they would not be regionally confined and also require highly specific target genes. CONCLUSIONS Overall, our results suggest that CRISPR-based TA gene drives provide promising candidates for flexible ecological engineering strategies in a variety of organisms.
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Affiliation(s)
- Jackson Champer
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA.
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
| | - Isabel K Kim
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Samuel E Champer
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Andrew G Clark
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Philipp W Messer
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
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92
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Champer SE, Oh SY, Liu C, Wen Z, Clark AG, Messer PW, Champer J. Computational and experimental performance of CRISPR homing gene drive strategies with multiplexed gRNAs. SCIENCE ADVANCES 2020; 6:eaaz0525. [PMID: 32181354 PMCID: PMC7056305 DOI: 10.1126/sciadv.aaz0525] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 12/02/2019] [Indexed: 05/27/2023]
Abstract
The rapid evolution of resistance alleles poses a major obstacle for genetic manipulation of populations with CRISPR homing gene drives. One proposed solution is using multiple guide RNAs (gRNAs), allowing a drive to function even if some resistant target sites are present. Here, we develop a model of homing mechanisms parameterized by experimental studies. Our model incorporates several factors affecting drives with multiple gRNAs, including timing of cleavage, reduction in homology-directed repair efficiency due to imperfect homology, Cas9 activity saturation, gRNA activity level variance, and incomplete homology-directed repair. We find that homing drives have an optimal number of gRNAs, usually between two and eight, depending on the specific drive type and performance parameters. These results contradict the notion that resistance rates can be reduced to arbitrarily low levels by gRNA multiplexing and highlight the need for combined approaches to counter resistance evolution in CRISPR homing drives.
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Affiliation(s)
- Samuel E. Champer
- Department of Computational Biology, Cornell University, Ithaca, NY 14853, USA
| | - Suh Yeon Oh
- Department of Computational Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Chen Liu
- Department of Computational Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Zhaoxin Wen
- Department of Computational Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Andrew G. Clark
- Department of Computational Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Philipp W. Messer
- Department of Computational Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jackson Champer
- Department of Computational Biology, Cornell University, Ithaca, NY 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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93
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Champer J, Lee E, Yang E, Liu C, Clark AG, Messer PW. A toxin-antidote CRISPR gene drive system for regional population modification. Nat Commun 2020; 11:1082. [PMID: 32109227 PMCID: PMC7046741 DOI: 10.1038/s41467-020-14960-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 02/06/2020] [Indexed: 01/04/2023] Open
Abstract
Engineered gene drives based on a homing mechanism could rapidly spread genetic alterations through a population. However, such drives face a major obstacle in the form of resistance against the drive. In addition, they are expected to be highly invasive. Here, we introduce the Toxin-Antidote Recessive Embryo (TARE) drive. It functions by disrupting a target gene, forming recessive lethal alleles, while rescuing drive-carrying individuals with a recoded version of the target. Modeling shows that such drives will have threshold-dependent invasion dynamics, spreading only when introduced above a fitness-dependent frequency. We demonstrate a TARE drive in Drosophila with 88-95% transmission by female heterozygotes. This drive was able to spread through a large cage population in just six generations following introduction at 24% frequency without any apparent evolution of resistance. Our results suggest that TARE drives constitute promising candidates for the development of effective, flexible, and regionally confinable drives for population modification.
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Affiliation(s)
- Jackson Champer
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA.
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
| | - Esther Lee
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Emily Yang
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Chen Liu
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Andrew G Clark
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Philipp W Messer
- Department of Computational Biology, Cornell University, Ithaca, NY, 14853, USA.
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94
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Famakinde DO. Public health concerns over gene-drive mosquitoes: will future use of gene-drive snails for schistosomiasis control gain increased level of community acceptance? Pathog Glob Health 2020; 114:55-63. [PMID: 32100643 DOI: 10.1080/20477724.2020.1731667] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
With the advent of CRISPR (clustered regularly interspaced short palindromic repeat)-based gene drive, present genetic research in schistosomiasis vector control envisages the breeding and release of transgenic schistosome-resistant (TSR) snail vectors to curb the spread of the disease. Although this approach is still in its infancy, studies focussing on production of genetically modified (GM) mosquitoes (including gene-drive mosquitoes) are well advanced and set the pace for other transgenic vector research. Unfortunately, as with other GM mosquitoes, open field release of gene-drive mosquitoes is currently challenged in part by some concerns such as gene drive failure and increased transmission potential for other mosquito-borne diseases among others, which might have adverse effects on human well-being. Therefore, not only should we learn from the GM mosquito protocols, frameworks and guidelines but also appraise the applicability of its current hurdles to other transgenic vector systems, such as the TSR snail approach. Placing these issues in a coherent comparative perspective, I argue that although the use of TSR snails may face similar technical, democratic and diplomatic challenges, some of the concerns over gene-drive mosquitoes may not apply to gene-drive snails, proposing a theory that community consent will be no harder and possibly easier to obtain for TSR snails than the experience with GM mosquitoes. In the future, these observations may help public health practitioners and policy makers in effective communication with communities on issues regarding the use of TSR snails to interrupt schistosomiasis transmission, especially in sub-Saharan Africa.
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Affiliation(s)
- Damilare O Famakinde
- Department of Medical Microbiology and Parasitology, University of Lagos, Lagos, Nigeria
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95
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Genetic Variation and Potential for Resistance Development to the tTA Overexpression Lethal System in Insects. G3 (BETHESDA, MD.) 2020; 10:1271-1281. [PMID: 32019873 PMCID: PMC7144068 DOI: 10.1534/g3.120.400990] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Release of insect pests carrying the dominant lethal tetracycline transactivator (tTA) overexpression system has been proposed as a means for population suppression. High levels of the tTA transcription factor are thought to be toxic due to either transcriptional squelching or interference with protein ubiquitination. Here we utilized the Drosophila melanogaster Genetic Reference Panel (DGRP) to examine the influence of genetic variation on the efficacy of a female-specific tTA overexpression system. The level of female lethality between DGRP lines varied from 11 to 97% with a broad sense heritability of 0.89. A genome-wide association analysis identified 192 allelic variants associated with high or low lethality (P < 10-5), although none were significant when corrected for multiple testing. 151 of the variants fell within 108 genes that were associated with several biological processes including transcription and protein ubiquitination. In four lines with high female lethality, tTA RNA levels were similar or higher than in the parental tTA overexpression strain. In two lines with low lethality, tTA levels were about two fold lower than in the parental strain. However, in two other lines with low lethality, tTA levels were similar or approximately 30% lower. RNAseq analysis identified genes that were up or downregulated in the four low female lethal lines compared to the four high lethal lines. For example, genes associated with RNA processing and rRNA maturation were significantly upregulated in low lethal lines. Our data suggest that standing genetic variation in an insect population could provide multiple mechanisms for resistance to the tTA overexpression system.
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96
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King JG. Developmental and comparative perspectives on mosquito immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 103:103458. [PMID: 31377103 DOI: 10.1016/j.dci.2019.103458] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 07/30/2019] [Accepted: 07/30/2019] [Indexed: 06/10/2023]
Abstract
Diseases spread by mosquitoes have killed more people than those spread by any other group of arthropod vectors and remain an important factor in determining global health and economic stability. The mosquito innate immune system can act to either modulate infection with human pathogens or fight off entomopathogens and increase the fitness and longevity of infected mosquitoes. While work remains towards understanding the larval immune system and the development of the mosquito immune system, it has recently become clearer that environmental factors heavily shape the developing mosquito immune system and continue to influence the adult immune system as well. The adult immune system has been well-studied and is known to involve multiple tissues and diverse molecular mechanisms. This review summarizes and synthesizes what is currently understood about the development of the mosquito immune system and includes comparisons of immune components unique to mosquitoes among the blood-feeding arthropods as well as important distinguishing factors between the anopheline and culicine mosquitoes. An explanation is included for how mosquito immunity factors into vector competence and vectorial capacity is presented along with a model for the interrelationships between nutrition, microbiome, pathogen interactions and behavior as they relate to mosquito development, immune status, adult female fitness and ultimately, vectorial capacity. Novel discoveries in the fields of mosquito ecoimmunology, neuroimmunology, and intracellular antiviral responses are highlighted.
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Affiliation(s)
- Jonas G King
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, 32 Creelman Street, Dorman 402, Mississippi State, MS 39762, USA.
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97
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Bergey CM, Lukindu M, Wiltshire RM, Fontaine MC, Kayondo JK, Besansky NJ. Assessing connectivity despite high diversity in island populations of a malaria mosquito. Evol Appl 2020; 13:417-431. [PMID: 31993086 PMCID: PMC6976967 DOI: 10.1111/eva.12878] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/28/2019] [Accepted: 09/27/2019] [Indexed: 12/14/2022] Open
Abstract
Documenting isolation is notoriously difficult for species with vast polymorphic populations. High proportions of shared variation impede estimation of connectivity, even despite leveraging information from many genetic markers. We overcome these impediments by combining classical analysis of neutral variation with assays of the structure of selected variation, demonstrated using populations of the principal African malaria vector Anopheles gambiae. Accurate estimation of mosquito migration is crucial for efforts to combat malaria. Modeling and cage experiments suggest that mosquito gene drive systems will enable malaria eradication, but establishing safety and efficacy requires identification of isolated populations in which to conduct field testing. We assess Lake Victoria islands as candidate sites, finding one island 30 km offshore is as differentiated from mainland samples as populations from across the continent. Collectively, our results suggest sufficient contemporary isolation of these islands to warrant consideration as field-testing locations and illustrate shared adaptive variation as a useful proxy for connectivity in highly polymorphic species.
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Affiliation(s)
- Christina M. Bergey
- Department of Biological SciencesUniversity of Notre DameNotre DameINUSA
- Eck Institute for Global HealthUniversity of Notre DameNotre DameINUSA
- Department of GeneticsRutgers UniversityPiscatawayNJUSA
- Departments of Anthropology and BiologyPennsylvania State UniversityUniversity ParkPAUSA
| | - Martin Lukindu
- Department of Biological SciencesUniversity of Notre DameNotre DameINUSA
- Eck Institute for Global HealthUniversity of Notre DameNotre DameINUSA
| | - Rachel M. Wiltshire
- Department of Biological SciencesUniversity of Notre DameNotre DameINUSA
- Eck Institute for Global HealthUniversity of Notre DameNotre DameINUSA
| | - Michael C. Fontaine
- Groningen Institute for Evolutionary Life Sciences (GELIFES)University of GroningenGroningenThe Netherlands
- MIVEGECIRDCNRSUniversity of MontpellierMontpellierFrance
| | | | - Nora J. Besansky
- Department of Biological SciencesUniversity of Notre DameNotre DameINUSA
- Eck Institute for Global HealthUniversity of Notre DameNotre DameINUSA
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98
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Pejchar L, Lepczyk CA, Fantle-Lepczyk JE, Hess SC, Johnson MT, Leopold CR, Marchetti M, McClure KM, Shiels AB. Hawaii as a Microcosm: Advancing the Science and Practice of Managing Introduced and Invasive Species. Bioscience 2020. [DOI: 10.1093/biosci/biz154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Invasive species are a leading driver of global change, with consequences for biodiversity and society. Because of extraordinary rates of endemism, introduction, and extinction, Hawaii offers a rich platform for exploring the cross-disciplinary challenges of managing invasive species in a dynamic world. We highlight key successes and shortcomings to share lessons learned and inspire innovation and action in and beyond the archipelago. We then discuss thematic challenges and opportunities of broad relevance to invaded ecosystems and human communities. Important research needs and possible actions include eradicating mammals from mainland island sanctuaries, assessing hidden threats from poorly known introduced species, harnessing genomic tools to eradicate disease vectors, structured decision-making to achieve common objectives among diverse stakeholders, and enhancing capacity through nontraditional funding streams and progressive legislation. By shining a spotlight on invasive species at the front lines in Hawaii, we hope to catalyze strategic research and practice to help inform scientists and policymakers.
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Affiliation(s)
| | | | | | - Steven C Hess
- US Geological Survey Pacific Islands Ecosystems Research Station, Hawaii Volcanoes National Park, Hawaii
| | - M Tracy Johnson
- US Department of Agriculture Forest Service, Hawaii Volcanoes National Park, Hawaii
| | | | | | - Katherine M McClure
- University of California Santa Cruz when this project began and is now a postdoctoral fellow at Cornell University in Ithaca, New York
| | - Aaron B Shiels
- USDA Animal and Plant Health Inspection Service National Wildlife Research Center, Fort Collins, Colorado
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99
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Xu X, Wang Y, Bi H, Xu J, Liu Z, Niu C, He L, James AA, Li K, Huang Y. Mutation of the seminal protease gene, serine protease 2, results in male sterility in diverse lepidopterans. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 116:103243. [PMID: 31541694 DOI: 10.1016/j.ibmb.2019.103243] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/04/2019] [Accepted: 09/14/2019] [Indexed: 06/10/2023]
Abstract
Sterile insect technology (SIT) is an environmentally friendly method for pest control. As part of our efforts to develop a strategy that results in engineered male-sterile strains with minimum effects on viability and mating competition, we used CRISPR/Cas9 technology to disrupt Ser2, which encodes a seminal fluid protein, in the model lepidopteran insect, Bombyx mori, and an important agricultural pest, Plutella xylostella. Disruption of Ser2 resulted in dominant heritable male sterility. Wild-type females mated with Ser2-deficient males laid eggs normally, but the eggs did not hatch. We detected no differences in other reproductive behaviors in the mutant males. These results support the conclusion that Ser2 gene is necessary for male reproductive success in diverse lepidopterans. Targeting Ser2 gene has the potential to form the basis for a new strategy for pest control.
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Affiliation(s)
- Xia Xu
- School of Life Science, East China Normal University, 200241, Shanghai, China; Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Yaohui Wang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China; Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China
| | - Honglun Bi
- School of Life Science, East China Normal University, 200241, Shanghai, China; Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Jun Xu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Zulian Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Changying Niu
- Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China
| | - Lin He
- School of Life Science, East China Normal University, 200241, Shanghai, China.
| | - Anthony A James
- Department of Microbiology & Molecular Genetics and Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697-3900, USA
| | - Kai Li
- School of Life Science, East China Normal University, 200241, Shanghai, China.
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China.
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100
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Suresh M, Jeevanandam J, Chan YS, Danquah MK, Kalaiarasi JMV. Opportunities for Metal Oxide Nanoparticles as a Potential Mosquitocide. BIONANOSCIENCE 2019. [DOI: 10.1007/s12668-019-00703-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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