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Connolly JB, Burt A, Christophides G, Diabate A, Habtewold T, Hancock PA, James AA, Kayondo JK, Lwetoijera DW, Manjurano A, McKemey AR, Santos MR, Windbichler N, Randazzo F. Considerations for first field trials of low-threshold gene drive for malaria vector control. Malar J 2024; 23:156. [PMID: 38773487 PMCID: PMC11110314 DOI: 10.1186/s12936-024-04952-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 04/15/2024] [Indexed: 05/23/2024] Open
Abstract
Sustainable reductions in African malaria transmission require innovative tools for mosquito control. One proposal involves the use of low-threshold gene drive in Anopheles vector species, where a 'causal pathway' would be initiated by (i) the release of a gene drive system in target mosquito vector species, leading to (ii) its transmission to subsequent generations, (iii) its increase in frequency and spread in target mosquito populations, (iv) its simultaneous propagation of a linked genetic trait aimed at reducing vectorial capacity for Plasmodium, and (v) reduced vectorial capacity for parasites in target mosquito populations as the gene drive system reaches fixation in target mosquito populations, causing (vi) decreased malaria incidence and prevalence. Here the scope, objectives, trial design elements, and approaches to monitoring for initial field releases of such gene dive systems are considered, informed by the successful implementation of field trials of biological control agents, as well as other vector control tools, including insecticides, Wolbachia, larvicides, and attractive-toxic sugar bait systems. Specific research questions to be addressed in initial gene drive field trials are identified, and adaptive trial design is explored as a potentially constructive and flexible approach to facilitate testing of the causal pathway. A fundamental question for decision-makers for the first field trials will be whether there should be a selective focus on earlier points of the pathway, such as genetic efficacy via measurement of the increase in frequency and spread of the gene drive system in target populations, or on wider interrogation of the entire pathway including entomological and epidemiological efficacy. How and when epidemiological efficacy will eventually be assessed will be an essential consideration before decisions on any field trial protocols are finalized and implemented, regardless of whether initial field trials focus exclusively on the measurement of genetic efficacy, or on broader aspects of the causal pathway. Statistical and modelling tools are currently under active development and will inform such decisions on initial trial design, locations, and endpoints. Collectively, the considerations here advance the realization of developer ambitions for the first field trials of low-threshold gene drive for malaria vector control within the next 5 years.
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Affiliation(s)
- John B Connolly
- Department of Life Sciences, Silwood Park, Imperial College London, London, UK.
| | - Austin Burt
- Department of Life Sciences, Silwood Park, Imperial College London, London, UK
| | - George Christophides
- Department of Life Sciences, South Kensington Campus, Imperial College London, London, UK
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Tibebu Habtewold
- Department of Life Sciences, South Kensington Campus, Imperial College London, London, UK
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Penelope A Hancock
- MRC Centre for Global Infectious Disease Analysis, St. Mary's Campus, Imperial College London, London, UK
| | - Anthony A James
- Departments of Microbiology & Molecular Genetics and Molecular Biology & Biochemistry, University of California, Irvine, USA
| | - Jonathan K Kayondo
- Entomology Department, Uganda Virus Research Institute (UVRI), Entebbe, Uganda
| | | | - Alphaxard Manjurano
- Malaria Research Unit and Laboratory Sciences, Mwanza Medical Research Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Andrew R McKemey
- Department of Life Sciences, Silwood Park, Imperial College London, London, UK
| | - Michael R Santos
- Foundation for the National Institutes of Health, North Bethesda, MD, USA
| | - Nikolai Windbichler
- Department of Life Sciences, South Kensington Campus, Imperial College London, London, UK
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de Haas FJH, Kläy L, Débarre F, Otto SP. Modelling daisy quorum drive: A short-term bridge across engineered fitness valleys. PLoS Genet 2024; 20:e1011262. [PMID: 38753875 PMCID: PMC11135765 DOI: 10.1371/journal.pgen.1011262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/29/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024] Open
Abstract
Engineered gene-drive techniques for population modification and/or suppression have the potential for tackling complex challenges, including reducing the spread of diseases and invasive species. Gene-drive systems with low threshold frequencies for invasion, such as homing-based gene drive, require initially few transgenic individuals to spread and are therefore easy to introduce. The self-propelled behavior of such drives presents a double-edged sword, however, as the low threshold can allow transgenic elements to expand beyond a target population. By contrast, systems where a high threshold frequency must be reached before alleles can spread-above a fitness valley-are less susceptible to spillover but require introduction at a high frequency. We model a proposed drive system, called "daisy quorum drive," that transitions over time from a low-threshold daisy-chain system (involving homing-based gene drive such as CRISPR-Cas9) to a high-threshold fitness-valley system (requiring a high frequency-a "quorum"-to spread). The daisy-chain construct temporarily lowers the high thresholds required for spread of the fitness-valley construct, facilitating use in a wide variety of species that are challenging to breed and release in large numbers. Because elements in the daisy chain only drive subsequent elements in the chain and not themselves and also carry deleterious alleles ("drive load"), the daisy chain is expected to exhaust itself, removing all CRISPR elements and leaving only the high-threshold fitness-valley construct, whose spread is more spatially restricted. Developing and analyzing both discrete patch and continuous space models, we explore how various attributes of daisy quorum drive affect the chance of modifying local population characteristics and the risk that transgenic elements expand beyond a target area. We also briefly explore daisy quorum drive when population suppression is the goal. We find that daisy quorum drive can provide a promising bridge between gene-drive and fitness-valley constructs, allowing spread from a low frequency in the short term and better containment in the long term, without requiring repeated introductions or persistence of CRISPR elements.
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Affiliation(s)
- Frederik J. H. de Haas
- Biodiversity Research Center, Department of Zoology, University of British Columbia, Vancouver BC, Canada
| | - Léna Kläy
- Institute of Ecology and Environmental Sciences Paris (IEES Paris), Sorbonne Université, CNRS, IRD, INRAE, Université Paris Est Creteil, Université de Paris, Paris Cedex 5, France
| | - Florence Débarre
- Institute of Ecology and Environmental Sciences Paris (IEES Paris), Sorbonne Université, CNRS, IRD, INRAE, Université Paris Est Creteil, Université de Paris, Paris Cedex 5, France
| | - Sarah P. Otto
- Biodiversity Research Center, Department of Zoology, University of British Columbia, Vancouver BC, Canada
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Kormos A, Dimopoulos G, Bier E, Lanzaro GC, Marshall JM, James AA. Conceptual risk assessment of mosquito population modification gene-drive systems to control malaria transmission: preliminary hazards list workshops. Front Bioeng Biotechnol 2023; 11:1261123. [PMID: 37965050 PMCID: PMC10641379 DOI: 10.3389/fbioe.2023.1261123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/09/2023] [Indexed: 11/16/2023] Open
Abstract
The field-testing and eventual adoption of genetically-engineered mosquitoes (GEMs) to control vector-borne pathogen transmission will require them meeting safety criteria specified by regulatory authorities in regions where the technology is being considered for use and other locales that might be impacted. Preliminary risk considerations by researchers and developers may be useful for planning the baseline data collection and field research used to address the anticipated safety concerns. Part of this process is to identify potential hazards (defined as the inherent ability of an entity to cause harm) and their harms, and then chart the pathways to harm and evaluate their probability as part of a risk assessment. The University of California Malaria Initiative (UCMI) participated in a series of workshops held to identify potential hazards specific to mosquito population modification strains carrying gene-drive systems coupled to anti-parasite effector genes and their use in a hypothetical island field trial. The hazards identified were placed within the broader context of previous efforts discussed in the scientific literature. Five risk areas were considered i) pathogens, infections and diseases, and the impacts of GEMs on human and animal health, ii) invasiveness and persistence of GEMs, and interactions of GEMs with target organisms, iii) interactions of GEMs with non-target organisms including horizontal gene transfer, iv) impacts of techniques used for the management of GEMs and v) evolutionary and stability considerations. A preliminary hazards list (PHL) was developed and is made available here. This PHL is useful for internal project risk evaluation and is available to regulators at prospective field sites. UCMI project scientists affirm that the subsequent processes associated with the comprehensive risk assessment for the application of this technology should be driven by the stakeholders at the proposed field site and areas that could be affected by this intervention strategy.
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Affiliation(s)
- Ana Kormos
- Vector Genetics Laboratory, University of California, Davis, Davis, CA, United States
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Malaria Research Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Ethan Bier
- Department of Cell and Developmental Biology, University of California, San Diego, San Diego, CA, United States
| | - Gregory C. Lanzaro
- Vector Genetics Laboratory, University of California, Davis, Davis, CA, United States
| | - John M. Marshall
- Divisions of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Anthony A. James
- Departments of Microbiology and Molecular Genetics and Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, United States
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Qureshi A, Connolly JB. Bioinformatic and literature assessment of toxicity and allergenicity of a CRISPR-Cas9 engineered gene drive to control Anopheles gambiae the mosquito vector of human malaria. Malar J 2023; 22:234. [PMID: 37580703 PMCID: PMC10426224 DOI: 10.1186/s12936-023-04665-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 08/07/2023] [Indexed: 08/16/2023] Open
Abstract
BACKGROUND Population suppression gene drive is currently being evaluated, including via environmental risk assessment (ERA), for malaria vector control. One such gene drive involves the dsxFCRISPRh transgene encoding (i) hCas9 endonuclease, (ii) T1 guide RNA (gRNA) targeting the doublesex locus, and (iii) DsRed fluorescent marker protein, in genetically-modified mosquitoes (GMMs). Problem formulation, the first stage of ERA, for environmental releases of dsxFCRISPRh previously identified nine potential harms to the environment or health that could occur, should expressed products of the transgene cause allergenicity or toxicity. METHODS Amino acid sequences of hCas9 and DsRed were interrogated against those of toxins or allergens from NCBI, UniProt, COMPARE and AllergenOnline bioinformatic databases and the gRNA was compared with microRNAs from the miRBase database for potential impacts on gene expression associated with toxicity or allergenicity. PubMed was also searched for any evidence of toxicity or allergenicity of Cas9 or DsRed, or of the donor organisms from which these products were originally derived. RESULTS While Cas9 nuclease activity can be toxic to some cell types in vitro and hCas9 was found to share homology with the prokaryotic toxin VapC, there was no evidence from previous studies of a risk of toxicity to humans and other animals from hCas9. Although hCas9 did contain an 8-mer epitope found in the latex allergen Hev b 9, the full amino acid sequence of hCas9 was not homologous to any known allergens. Combined with a lack of evidence in the literature of Cas9 allergenicity, this indicated negligible risk to humans of allergenicity from hCas9. No matches were found between the gRNA and microRNAs from either Anopheles or humans. Moreover, potential exposure to dsxFCRISPRh transgenic proteins from environmental releases was assessed as negligible. CONCLUSIONS Bioinformatic and literature assessments found no convincing evidence to suggest that transgenic products expressed from dsxFCRISPRh were allergens or toxins, indicating that environmental releases of this population suppression gene drive for malaria vector control should not result in any increased allergenicity or toxicity in humans or animals. These results should also inform evaluations of other GMMs being developed for vector control and in vivo clinical applications of CRISPR-Cas9.
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Affiliation(s)
- Alima Qureshi
- Department of Life Sciences, Imperial College London, Silwood Park, Sunninghill, Ascot, UK
| | - John B Connolly
- Department of Life Sciences, Imperial College London, Silwood Park, Sunninghill, Ascot, UK.
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Combs MA, Golnar AJ, Overcash JM, Lloyd AL, Hayes KR, O'Brochta DA, Pepin KM. Leveraging eco-evolutionary models for gene drive risk assessment. Trends Genet 2023:S0168-9525(23)00090-2. [PMID: 37198063 DOI: 10.1016/j.tig.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/07/2023] [Accepted: 04/14/2023] [Indexed: 05/19/2023]
Abstract
Engineered gene drives create potential for both widespread benefits and irreversible harms to ecosystems. CRISPR-based systems of allelic conversion have rapidly accelerated gene drive research across diverse taxa, putting field trials and their necessary risk assessments on the horizon. Dynamic process-based models provide flexible quantitative platforms to predict gene drive outcomes in the context of system-specific ecological and evolutionary features. Here, we synthesize gene drive dynamic modeling studies to highlight research trends, knowledge gaps, and emergent principles, organized around their genetic, demographic, spatial, environmental, and implementation features. We identify the phenomena that most significantly influence model predictions, discuss limitations of biological complexity and uncertainty, and provide insights to promote responsible development and model-assisted risk assessment of gene drives.
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Affiliation(s)
- Matthew A Combs
- National Wildlife Research Center, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Fort Collins, CO, 80521, USA.
| | - Andrew J Golnar
- National Wildlife Research Center, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Fort Collins, CO, 80521, USA
| | - Justin M Overcash
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Biotechnology Regulatory Services, 20737, USA
| | - Alun L Lloyd
- North Carolina State University, Biomathematics Graduate Program and Department of Mathematics, Raleigh, NC, 27695, USA
| | - Keith R Hayes
- The Commonwealth Scientific and Industrial Research Organisation, Data 61, Hobart, TAS, 7004, Australia
| | - David A O'Brochta
- Foundation for the National Institutes of Health, North Bethesda, MD, 20852, USA
| | - Kim M Pepin
- National Wildlife Research Center, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Fort Collins, CO, 80521, USA
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Frieß JL, Lalyer CR, Giese B, Simon S, Otto M. Review of gene drive modelling and implications for risk assessment of gene drive organisms. Ecol Modell 2023. [DOI: 10.1016/j.ecolmodel.2023.110285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Gene drive in species complexes: defining target organisms. Trends Biotechnol 2023; 41:154-164. [PMID: 35868886 DOI: 10.1016/j.tibtech.2022.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/17/2022] [Accepted: 06/27/2022] [Indexed: 01/24/2023]
Abstract
Engineered gene drives, which bias their own inheritance to increase in frequency in target populations, are being developed to control mosquito malaria vectors. Such mosquitoes can belong to complexes of both vector and nonvector species that can produce fertile interspecific hybrids, making vertical gene drive transfer (VGDT) to sibling species biologically plausible. While VGDT to other vectors could positively impact human health protection goals, VGDT to nonvectors might challenge biodiversity ones. Therefore, environmental risk assessment of gene drive use in species complexes invites more nuanced considerations of target organisms and nontarget organisms than for transgenes not intended to increase in frequency in target populations. Incorporating the concept of target species complexes offers more flexibility when assessing potential impacts from VGDT.
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8
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Resnik DB, Medina RF, Gould F, Church G, Kuzma J. Genes drive organisms and slippery slopes. Pathog Glob Health 2022:1-10. [PMID: 36562087 DOI: 10.1080/20477724.2022.2160895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The bioethical debate about using gene drives to alter or eradicate wild populations has focused mostly on issues concerning short-term risk assessment and management, governance and oversight, and public and community engagement, but has not examined big-picture- 'where is this going?'-questions in great depth. In other areas of bioethical controversy, big-picture questions often enter the public forum via slippery slope arguments. Given the incredible potential of gene drive organisms to alter the Earth's biota, it is somewhat surprising that slippery slope arguments have not played a more prominent role in ethical and policy debates about these emerging technologies. In this article, we examine a type of slippery slope argument against using gene drives to alter or suppress wild pest populations and consider whether it has a role to play in ethical and policy debates. Although we conclude that this argument does not provide compelling reasons for banning the use of gene drives in wild pest populations, we believe that it still has value as a morally instructive cautionary narrative that can motivate scientists, ethicists, and members of the public to think more clearly about appropriate vs. inappropriate uses of gene drive technologies, the long-term and cumulative and emergent risks of using gene drives in wild populations, and steps that can be taken to manage these risks, such as protecting wilderness areas where people can enjoy life forms that have not been genetically engineered.
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Affiliation(s)
- David B Resnik
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Raul F Medina
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Fred Gould
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - George Church
- Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, MA, USA
| | - Jennifer Kuzma
- School of Public and International Affairs, North Carolina State University, Raleigh, NC, USA
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Brown EA, Eikenbary SR, Landis WG. Bayesian network-based risk assessment of synthetic biology: Simulating CRISPR-Cas9 gene drive dynamics in invasive rodent management. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2022; 42:2835-2846. [PMID: 35568962 DOI: 10.1111/risa.13948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Gene drive technology has been proposed to control invasive rodent populations as an alternative to rodenticides. However, this approach has not undergone risk assessment that meets criteria established by Gene Drives on the Horizon, a 2016 report by the National Academies of Sciences, Engineering, and Medicine. To conduct a risk assessment of gene drives, we employed the Bayesian network-relative risk model to calculate the risk of mouse eradication on Southeast Farallon Island using a CRISPR-Cas9 homing gene drive construct. We modified and implemented the R-based model "MGDrivE" to simulate and compare 60 management strategies for gene drive rodent management. These scenarios spanned four gene drive mouse release schemes, three gene drive homing rates, three levels of supplemental rodenticide dose, and two timings of rodenticide application relative to gene drive release. Simulation results showed that applying a supplemental rodenticide simultaneously with gene drive mouse deployment resulted in faster eradication of the island mouse population. Gene drive homing rate had the highest influence on the overall probability of successful eradication, as increased gene drive accuracy reduces the likelihood of mice developing resistance to the CRISPR-Cas9 homing mechanism.
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Affiliation(s)
- Ethan A Brown
- Institute of Environmental Toxicology and Chemistry, College of the Environment, Western Washington University, Bellingham, Washington, USA
| | - Steven R Eikenbary
- Institute of Environmental Toxicology and Chemistry, College of the Environment, Western Washington University, Bellingham, Washington, USA
| | - Wayne G Landis
- Institute of Environmental Toxicology and Chemistry, College of the Environment, Western Washington University, Bellingham, Washington, USA
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Macfarlane NB, Adams J, Bennett EL, Brooks TM, Delborne JA, Eggermont H, Endy D, Esvelt KM, Kolodziejczyk B, Kuiken T, Oliva MJ, Peña Moreno S, Slobodian L, Smith RB, Thizy D, Tompkins DM, Wei W, Redford KH. Direct and indirect impacts of synthetic biology on biodiversity conservation. iScience 2022; 25:105423. [DOI: 10.1016/j.isci.2022.105423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Modeling the efficacy of CRISPR gene drive for snail immunity on schistosomiasis control. PLoS Negl Trop Dis 2022; 16:e0010894. [DOI: 10.1371/journal.pntd.0010894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/10/2022] [Accepted: 10/14/2022] [Indexed: 11/05/2022] Open
Abstract
CRISPR gene drives could revolutionize the control of infectious diseases by accelerating the spread of engineered traits that limit parasite transmission in wild populations. Gene drive technology in mollusks has received little attention despite the role of freshwater snails as hosts of parasitic flukes causing 200 million annual cases of schistosomiasis. A successful drive in snails must overcome self-fertilization, a common feature of host snails which could prevents a drive’s spread. Here we developed a novel population genetic model accounting for snails’ mixed mating and population dynamics, susceptibility to parasite infection regulated by multiple alleles, fitness differences between genotypes, and a range of drive characteristics. We integrated this model with an epidemiological model of schistosomiasis transmission to show that a snail population modification drive targeting immunity to infection can be hindered by a variety of biological and ecological factors; yet under a range of conditions, disease reduction achieved by chemotherapy treatment of the human population can be maintained with a drive. Alone a drive modifying snail immunity could achieve significant disease reduction in humans several years after release. These results indicate that gene drives, in coordination with existing public health measures, may become a useful tool to reduce schistosomiasis burden in selected transmission settings with effective CRISPR construct design and evaluation of the genetic and ecological landscape.
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Garrood WT, Cuber P, Willis K, Bernardini F, Page NM, Haghighat-Khah RE. Driving down malaria transmission with engineered gene drives. Front Genet 2022; 13:891218. [PMID: 36338968 PMCID: PMC9627344 DOI: 10.3389/fgene.2022.891218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 09/13/2022] [Indexed: 11/26/2022] Open
Abstract
The last century has witnessed the introduction, establishment and expansion of mosquito-borne diseases into diverse new geographic ranges. Malaria is transmitted by female Anopheles mosquitoes. Despite making great strides over the past few decades in reducing the burden of malaria, transmission is now on the rise again, in part owing to the emergence of mosquito resistance to insecticides, antimalarial drug resistance and, more recently, the challenges of the COVID-19 pandemic, which resulted in the reduced implementation efficiency of various control programs. The utility of genetically engineered gene drive mosquitoes as tools to decrease the burden of malaria by controlling the disease-transmitting mosquitoes is being evaluated. To date, there has been remarkable progress in the development of CRISPR/Cas9-based homing endonuclease designs in malaria mosquitoes due to successful proof-of-principle and multigenerational experiments. In this review, we examine the lessons learnt from the development of current CRISPR/Cas9-based homing endonuclease gene drives, providing a framework for the development of gene drive systems for the targeted control of wild malaria-transmitting mosquito populations that overcome challenges such as with evolving drive-resistance. We also discuss the additional substantial works required to progress the development of gene drive systems from scientific discovery to further study and subsequent field application in endemic settings.
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Affiliation(s)
- William T. Garrood
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Piotr Cuber
- Department of Molecular Biology, Core Research Laboratories, Natural History Museum, London, United Kingdom
| | - Katie Willis
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Federica Bernardini
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Nicole M. Page
- Department of Life Sciences, Imperial College London, London, United Kingdom
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Leung S, Windbichler N, Wenger EA, Bever CA, Selvaraj P. Population replacement gene drive characteristics for malaria elimination in a range of seasonal transmission settings: a modelling study. Malar J 2022; 21:226. [PMID: 35883100 PMCID: PMC9327287 DOI: 10.1186/s12936-022-04242-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 07/11/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Gene drives are a genetic engineering method where a suite of genes is inherited at higher than Mendelian rates and has been proposed as a promising new vector control strategy to reinvigorate the fight against malaria in sub-Saharan Africa. METHODS Using an agent-based model of malaria transmission with vector genetics, the impacts of releasing population-replacement gene drive mosquitoes on malaria transmission are examined and the population replacement gene drive system parameters required to achieve local elimination within a spatially-resolved, seasonal Sahelian setting are quantified. The performance of two different gene drive systems-"classic" and "integral"-are evaluated. Various transmission regimes (low, moderate, and high-corresponding to annual entomological inoculation rates of 10, 30, and 80 infectious bites per person) and other simultaneous interventions, including deployment of insecticide-treated nets (ITNs) and passive healthcare-seeking, are also simulated. RESULTS Local elimination probabilities decreased with pre-existing population target site resistance frequency, increased with transmission-blocking effectiveness of the introduced antiparasitic gene and drive efficiency, and were context dependent with respect to fitness costs associated with the introduced gene. Of the four parameters, transmission-blocking effectiveness may be the most important to focus on for improvements to future gene drive strains because a single release of classic gene drive mosquitoes is likely to locally eliminate malaria in low to moderate transmission settings only when transmission-blocking effectiveness is very high (above ~ 80-90%). However, simultaneously deploying ITNs and releasing integral rather than classic gene drive mosquitoes significantly boosts elimination probabilities, such that elimination remains highly likely in low to moderate transmission regimes down to transmission-blocking effectiveness values as low as ~ 50% and in high transmission regimes with transmission-blocking effectiveness values above ~ 80-90%. CONCLUSION A single release of currently achievable population replacement gene drive mosquitoes, in combination with traditional forms of vector control, can likely locally eliminate malaria in low to moderate transmission regimes within the Sahel. In a high transmission regime, higher levels of transmission-blocking effectiveness than are currently available may be required.
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Affiliation(s)
- Shirley Leung
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, WA, USA
| | - Nikolai Windbichler
- Department of Life Sciences, Imperial College London, South Kensington, London, UK
| | - Edward A Wenger
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, WA, USA
| | - Caitlin A Bever
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, WA, USA
| | - Prashanth Selvaraj
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, WA, USA.
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Larval mosquito management and risk to aquatic ecosystems: A comparative approach including current tactics and gene-drive Anopheles techniques. Transgenic Res 2022; 31:489-504. [PMID: 35798930 PMCID: PMC9489571 DOI: 10.1007/s11248-022-00315-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 06/13/2022] [Indexed: 11/23/2022]
Abstract
Genetic engineering of mosquitoes represents a promising tactic for reducing human suffering from malaria. Gene-drive techniques being developed that suppress or modify populations of Anopheles gambiae have the potential to be used with, or even possibly obviate, microbial and synthetic insecticides. However, these techniques are new and therefore there is attendant concern and uncertainty from regulators, policymakers, and the public about their environmental risks. Therefore, there is a need to assist decision-makers and public health stewards by assessing the risks associated with these newer mosquito management tactics so the risks can be compared as a basis for informed decision making. Previously, the effect of gene-drive mosquitoes on water quality in Africa was identified as a concern by stakeholders. Here, we use a comparative risk assessment approach for the effect of gene-drive mosquitoes on water quality in Africa. We compare the use of existing larvicides and the proposed genetic techniques in aquatic environments. Based on our analysis, we conclude that the tactic of gene-drive Anopheles for malaria management is unlikely to result in risks to aquatic environments that exceed current tactics for larval mosquitoes. As such, these new techniques would likely comply with currently recommended safety standards.
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Connolly JB, Mumford JD, Glandorf DCM, Hartley S, Lewis OT, Evans SW, Turner G, Beech C, Sykes N, Coulibaly MB, Romeis J, Teem JL, Tonui W, Lovett B, Mankad A, Mnzava A, Fuchs S, Hackett TD, Landis WG, Marshall JM, Aboagye-Antwi F. Recommendations for environmental risk assessment of gene drive applications for malaria vector control. Malar J 2022; 21:152. [PMID: 35614489 PMCID: PMC9131534 DOI: 10.1186/s12936-022-04183-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/11/2022] [Indexed: 11/11/2022] Open
Abstract
Building on an exercise that identified potential harms from simulated investigational releases of a population suppression gene drive for malaria vector control, a series of online workshops identified nine recommendations to advance future environmental risk assessment of gene drive applications.
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Affiliation(s)
- John B Connolly
- Department of Life Sciences, Imperial College London, Silwood Park, Sunninghill, Ascot, UK.
| | - John D Mumford
- Centre for Environmental Policy, Imperial College London, Silwood Park, Sunninghill, Ascot, UK
| | | | | | - Owen T Lewis
- Department of Zoology, University of Oxford, Oxford, UK
| | - Sam Weiss Evans
- Program On Science, Technology & Society, John F. Kennedy School of Government, Harvard University, Cambridge, MA, USA
| | - Geoff Turner
- Department of Life Sciences, Imperial College London, Silwood Park, Sunninghill, Ascot, UK
| | | | - Naima Sykes
- Department of Life Sciences, Imperial College London, Silwood Park, Sunninghill, Ascot, UK
| | - Mamadou B Coulibaly
- Malaria Research and Training Center (MRTC), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Jörg Romeis
- Research Division Agroecology and Environment, Agroscope, Zürich, Switzerland
| | - John L Teem
- Genetic Biocontrols LLC, Tallahassee, FL, USA
| | - Willy Tonui
- Environmental Health and Safety (EHS Consultancy) Ltd, Nairobi, Kenya
| | - Brian Lovett
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, USA
| | - Aditi Mankad
- CSIRO Synthetic Biology Future Science Platform, CSIRO Land & Water, Brisbane, Australia
| | - Abraham Mnzava
- African Leaders Malaria Alliance, Dar es Salaam, Tanzania
| | - Silke Fuchs
- Department of Life Sciences, Imperial College London, Silwood Park, Sunninghill, Ascot, UK
| | | | - Wayne G Landis
- Institute of Environmental Toxicology and Chemistry, College of the Environment, Western Washington University, Bellingham, WA, USA
| | - John M Marshall
- Divisions of Biostatistics and Epidemiology, School of Public Health, University of California, Berkeley, USA
| | - Fred Aboagye-Antwi
- Department of Animal Biology and Conservation Sciences, University of Ghana, Legon, Accra, Ghana
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16
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Lessons learned from the introduction of genetically engineered crops: relevance to gene drive deployment in Africa. Transgenic Res 2022; 31:285-311. [PMID: 35545692 PMCID: PMC9135826 DOI: 10.1007/s11248-022-00300-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 02/04/2022] [Indexed: 11/10/2022]
Abstract
The application of gene drives to achieve public health goals, such as the suppression of Anopheles gambiae populations, or altering their ability to sustain Plasmodium spp. infections, has received much attention from researchers. If successful, this genetic tool can contribute greatly to the wellbeing of people in regions severely affected by malaria. However, engineered gene drives are a product of genetic engineering, and the experience to date, gained through the deployment of genetically engineered (GE) crops, is that GE technology has had difficulty receiving public acceptance in Africa, a key region for the deployment of gene drives. The history of GE crop deployment in this region provides good lessons for the deployment of gene drives as well. GE crops have been in commercial production for 24 years, since the planting of the first GE soybean crop in 1996. During this time, regulatory approvals and farmer adoption of these crops has grown rapidly in the Americas, and to a lesser extent in Asia. Their safety has been recognized by numerous scientific organizations. Economic and health benefits have been well documented in the countries that have grown them. However, only one transgenic crop event is being grown in Europe, and only in two countries in that region. Europe has been extremely opposed to GE crops, due in large part to the public view of agriculture that opposes “industrial” farming. This attitude is reflected in a highly precautionary regulatory and policy environment, which has highly influenced how African countries have dealt with GE technology and are likely to be applied to future genetic technologies, including gene drives. Furthermore, a mistrust of government regulatory agencies, the publication of scientific reports claiming adverse effects of GE crops, the involvement of corporations as the first GE crop developers, the lack of identifiable consumer benefit, and low public understanding of the technology further contributed to the lack of acceptance. Coupled with more emotionally impactful messaging to the public by opposition groups and the general tendency of negative messages to be more credible than positive ones, GE crops failed to gain a place in European agriculture, thus influencing African acceptance and government policy. From this experience, the following lessons have been learned that would apply to the deployment of gene drives, in Africa: It will be important to establish trust in those who are developing the technology, as well as in those who are making regulatory decisions. Engagement of the community, where those who are involved are able to make genuine contributions to the decision-making process, are necessary to achieve that trust. The use of tools to facilitate participatory modeling could be considered in order to enhance current community engagement efforts. Trusted, accurate information on gene drives should be made available to the general public, journalists, and scientists who are not connected with the field. Those sources of information should also be able to summarize and analyze important scientific results and emerging issues in the field in order to place those developments in the proper context. Engagement should involve more opportunities for participation of stakeholders in conceptualizing, planning, and decision-making. Diversifying the source of funding for gene drive research and development, particularly by participation of countries and regional bodies, would show that country or regional interests are represented. Efforts by developers and neutral groups to provide the public and decisionmakers with a more thorough understanding of the benefits and risks of this technology, especially to local communities, would help them reach more informed decisions. A better understanding of gene drive technology can be fostered by governments, as part of established biosafety policy in several African countries. Developers and neutral groups could also be helpful in increasing public understanding of the technology of genetic engineering, including gene drives. Effective messaging to balance the messaging of groups opposed to gene drives is needed. These messages should be not only factual but also have emotional and intuitive appeal.
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Mondal A, Vásquez VN, Marshall JM. Target Product Profiles for Mosquito Gene Drives: Incorporating Insights From Mathematical Models. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.828876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mosquito-borne diseases such as malaria continue to pose a major global health burden, and the impact of currently-available interventions is stagnating. Consequently, there is interest in novel tools to control these diseases, including gene drive-modified mosquitoes. As these tools continue to be refined, decisions on whether to implement them in the field depend on their alignment with target product profiles (TPPs) that define product characteristics required to achieve desired entomological and epidemiological outcomes. TPPs are increasingly being used for malaria and vector control interventions, such as attractive targeted sugar baits and long-acting injectable drugs, as they progress through the development pipeline. For mosquito gene drive products, reliable predictions from mathematical models are an essential part of these analyses, as field releases could potentially be irreversible. Here, we review the prior use of mathematical models in developing TPPs for malaria and vector control tools and discuss lessons from these analyses that may apply to mosquito gene drives. We recommend that, as gene drive technology gets closer to field release, discussions regarding target outcomes engage a wide range of stakeholders and account for settings of interest and vector species present. Given the relatively large number of parameters that describe gene drive products, machine learning approaches may be useful to explore parameter space, and an emphasis on conservative fitness estimates is advisable, given the difficulty of accurately measuring these parameters prior to field studies. Modeling may also help to inform the risk, remediation and cost dimensions of mosquito gene drive TPPs.
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Qureshi A, Connolly JB. A systematic review assessing the potential for release of vector species from competition following insecticide-based population suppression of Anopheles species in Africa. Parasit Vectors 2021; 14:462. [PMID: 34496931 PMCID: PMC8425169 DOI: 10.1186/s13071-021-04975-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 08/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND While insecticide-based vector control can effectively target vector species in areas of high malaria endemicity, such as Anopheles gambiae in Africa, residual disease transmission can occur. Understanding the potential role of competitive displacement between vector species could inform both current insecticide-based vector control programmes and the development of future complementary interventions. METHODS A systematic review was conducted to identify published studies of insecticide-based vector control of Anopheles species in Africa that reported indices for absolute densities of vector species. After screening against inclusion, exclusion and risk of bias criteria, studies were assigned to three categories based on whether they showed population density changes involving decreases in two or more vector species (D), increases in two or more vector species (I), or increases in one vector species concomitant with decreases in another vector species (ID). Category ID studies could thus provide evidence consistent with the release of vector species from competition following the insecticide-based population suppression of Anopheles species. RESULTS Of 5569 papers identified in searches, 30 were selected for quantitative and qualitative analysis. Nineteen studies were assigned to category D and one to category I. Ten studies categorised as ID provided evidence ranging from weak to persuasive that release from competition could have contributed to changes in species composition. Category ID showed no statistical differences from category D for reductions in malaria transmission and levels of insecticide resistance, but did so for insecticide type, pyrethroids being associated with category ID. A qualitative assessment identified five studies that provided the most convincing evidence that release from competition could have contributed to changes in species composition. CONCLUSIONS This review identified evidence that insecticide-based reductions in the density of Anopheles species in Africa could facilitate the release of other vector species from competition. While it remains uncertain whether this evidence is representative of most entomological sequelae of insecticide-based vector control in the field, five studies provided persuasive evidence that insecticide use could lead, at least under some circumstances, to competitive release of non-targeted vector species. These results should inform current and future integrated vector management approaches to malaria control.
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Affiliation(s)
- Alima Qureshi
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY UK
| | - John B. Connolly
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY UK
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Adelman ZN, Kojin BB. Malaria-Resistant Mosquitoes (Diptera: Culicidae); The Principle is Proven, But Will the Effectors Be Effective? JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1997-2005. [PMID: 34018548 DOI: 10.1093/jme/tjab090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Over the last few decades, a substantial number of anti-malarial effector genes have been evaluated for their ability to block parasite infection in the mosquito vector. While many of these approaches have yielded significant effects on either parasite intensity or prevalence of infection, just a few have been able to completely block transmission. Additionally, many approaches, while effective against the parasite, also disrupt or alter important aspects of mosquito physiology, leading to corresponding changes in lifespan, reproduction, and immunity. As the most promising approaches move towards field-based evaluation, questions of effector gene robustness and durability move to the forefront. In this forum piece, we critically evaluate past effector gene approaches with an eye towards developing a deeper pipeline to augment the current best candidates.
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Affiliation(s)
- Zach N Adelman
- Department of Entomology and AgriLife Research, Texas A&M University, College Station, TX, USA
| | - Bianca B Kojin
- Department of Entomology and AgriLife Research, Texas A&M University, College Station, TX, USA
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Legros M, Marshall JM, Macfadyen S, Hayes KR, Sheppard A, Barrett LG. Gene drive strategies of pest control in agricultural systems: Challenges and opportunities. Evol Appl 2021; 14:2162-2178. [PMID: 34603490 PMCID: PMC8477592 DOI: 10.1111/eva.13285] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 06/24/2021] [Accepted: 07/19/2021] [Indexed: 12/18/2022] Open
Abstract
Recent advances in gene-editing technologies have opened new avenues for genetic pest control strategies, in particular around the use of gene drives to suppress or modify pest populations. Significant uncertainty, however, surrounds the applicability of these strategies to novel target species, their efficacy in natural populations and their eventual safety and acceptability as control methods. In this article, we identify issues associated with the potential use of gene drives in agricultural systems, to control pests and diseases that impose a significant cost to agriculture around the world. We first review the need for innovative approaches and provide an overview of the most relevant biological and ecological traits of agricultural pests that could impact the outcome of gene drive approaches. We then describe the specific challenges associated with using gene drives in agricultural systems, as well as the opportunities that these environments may offer, focusing in particular on the advantages of high-threshold gene drives. Overall, we aim to provide a comprehensive view of the potential opportunities and the remaining uncertainties around the use of gene drives in agricultural systems.
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Affiliation(s)
- Mathieu Legros
- CSIRO Agriculture and FoodCanberraACTAustralia
- CSIRO Synthetic Biology Future Science PlatformCanberraACTAustralia
| | - John M. Marshall
- Divisions of Biostatistics and Epidemiology – School of Public HealthUniversity of CaliforniaBerkeleyCAUSA
| | | | | | | | - Luke G. Barrett
- CSIRO Agriculture and FoodCanberraACTAustralia
- CSIRO Synthetic Biology Future Science PlatformCanberraACTAustralia
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21
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Devos Y, Mumford JD, Bonsall MB, Glandorf DCM, Quemada HD. Risk management recommendations for environmental releases of gene drive modified insects. Biotechnol Adv 2021; 54:107807. [PMID: 34314837 DOI: 10.1016/j.biotechadv.2021.107807] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 07/01/2021] [Accepted: 07/21/2021] [Indexed: 12/18/2022]
Abstract
The ability to engineer gene drives (genetic elements that bias their own inheritance) has sparked enthusiasm and concerns. Engineered gene drives could potentially be used to address long-standing challenges in the control of insect disease vectors, agricultural pests and invasive species, or help to rescue endangered species. However, risk concerns and uncertainty associated with potential environmental release of gene drive modified insects (GDMIs) have led some stakeholders to call for a global moratorium on such releases or the application of other strict precautionary measures to mitigate perceived risk assessment and risk management challenges. Instead, we provide recommendations that may help to improve the relevance of risk assessment and risk management frameworks for environmental releases of GDMIs. These recommendations include: (1) developing additional and more practical risk assessment guidance to ensure appropriate levels of safety; (2) making policy goals and regulatory decision-making criteria operational for use in risk assessment so that what constitutes harm is clearly defined; (3) ensuring a more dynamic interplay between risk assessment and risk management to manage uncertainty through closely interlinked pre-release modelling and post-release monitoring; (4) considering potential risks against potential benefits, and comparing them with those of alternative actions to account for a wider (management) context; and (5) implementing a modular, phased approach to authorisations for incremental acceptance and management of risks and uncertainty. Along with providing stakeholder engagement opportunities in the risk analysis process, the recommendations proposed may enable risk managers to make choices that are more proportionate and adaptive to potential risks, uncertainty and benefits of GDMI applications, and socially robust.
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Affiliation(s)
- Yann Devos
- Scientific Committee and Emerging Risk (SCER) Unit, European Food Safety Authority (EFSA), Parma, Italy.
| | - John D Mumford
- Centre for Environmental Policy, Imperial College London, Ascot, United Kingdom
| | | | - Debora C M Glandorf
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Hector D Quemada
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
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22
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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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