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Gene Drive Research: Why It Matters Cover Image Anopheles Gambiae © Jim Gathany-CDC Gene drive research: why it matters Cover image Anopheles gambiae © Jim Gathany-CDC. 2 GENE DRIVE RESEARCH: WHY IT MATTERS Gene drive research: why it matters Summary Gene drives are systems that bias the inheritance of a particular DNA Synthetic gene drives are being developed sequence. Many such systems occur naturally and scientists are now for a range of investigating the potential to develop new ones using synthetic biology purposes that would techniques. Synthetic gene drives are being developed for a range of benefit humanity but purposes that would benefit humanity, but it is not possible at this stage it is not possible at this stage to know whether to know whether the benefits outweigh the risks. Further research will the benefits outweigh help to reduce uncertainties and characterise potential risks and benefits. the risks. It is important that any research that does proceed is appropriately governed and combined with public debate. The Royal Society therefore recommends that the UN Convention on Biological Diversity avoid the adoption of any position that would support an international moratorium on gene drive research, including experimental field trials. Synthetic biology and gene drives biology applications, gene drives are Synthetic biology builds on established intended for use in wild populations, such technologies for changing DNA in existing as insects that carry diseases. So organisms organisms by using engineering principles containing gene drives are intended for to design and assemble new biological deliberate release into the environment. components and systems. The ability Some gene drives are also designed to to develop synthetic gene drives has spread within specific wild populations in a become increasingly feasible in recent self-sustaining way. These characteristics years thanks to the emergence of genome have led to considerable international editing technologies. Unlike many synthetic debate around the technology¹. 1. Sackler Forum 2015: Trends in synthetic biology and gain of function and regulatory implications. The Royal Society (2016). GENE DRIVE RESEARCH: WHY IT MATTERS 3 Gene drive applications Managing risks and benefits Scientists are also Gene drives are being developed for a range Despite their possible benefits, gene working on ways of purposes and sectors. Perhaps the most drives also carry risks since the broader of assessing and prominent of these is to reduce the populations ecological consequences of reducing or mitigating some of of malaria-transmitting mosquitoes². In this eliminating a population can be uncertain. the risks posed by context, gene drives have been proposed as Confinement strategies, safeguards and gene drives. providing a new means of tackling a disease appropriate governance for their use will be that still infects 200 million people and causes critically important5,6. Researchers working half a million deaths each year³. on gene drives are mindful of these risks and have called for a close assessment of Other applications under development include the technology’s potential impacts; not just providing a targeted means of controlling scientifically but in a much broader sense, or eradicating invasive species⁴. Figure 1 encompassing societal impacts, public summarises some of the proposed applications perception and acceptance, ecological and for gene drives. health impacts, biosafety and biosecurity issues, as well as how regulation and other forms of governance might manage the risks and promote the benefits7. 2. Further information in Box 2 on p.23 of Sackler Forum 2015: Trends in synthetic biology and gain of function and regulatory implications. The Royal Society (2016) 3. World Malaria Report. World Health Organisation (2015). 4. Esvelt, K.M., Smidler, A.L., Catteruccia, F., Church, G.M. Concerning RNA-guided gene drives for the alteration of wild populations. eLife. 2014; 3: e03401 5. Sackler Forum 2015: Trends in synthetic biology and gain of function and regulatory implications. The Royal Society (2016). 6. Hammond, A., Galizi, R., Kyrou, K., Simoni, A., Siniscalchi, C., Katsanos, D., Gribble, M., Baker, D., Marois, E., Russell, A., Burt, A., Windcihler, N., Crisanti, A., Nolan, T., 2016. A CRISPR-Cas9 gene drive system targeting female reproduction in the malaria mosquito vector Anopheles gambiae. Nature Biotechnology. 34: 78 - 83. 7. Op. cit. note 5. 4 GENE DRIVE RESEARCH: WHY IT MATTERS FIGURE 1 Speculative possible uses for gene drives. Of these, controlling vector-borne disease and controlling invasive species are the two most actively researched areas8. 8. Figure reproduced from Figure 5 on p.22 of Sackler Forum 2015: Trends in synthetic biology and gain of function and regulatory implications. The Royal Society (2016). GENE DRIVE RESEARCH: WHY IT MATTERS 5 To implement this close assessment, Scientists are also working on ways of the scientific community has called for assessing and mitigating some of the risks transparency from the outset of research, posed by gene drives. Organisms should be including discussion with the public preceding assessed on a case-by-case basis, based on some research projects and certainly lessons learned from the release of organisms taking place before any release of modified that have been genetically modified but organisms into the environment9. It will also not with a gene drive11. One of the simplest be important to develop interdisciplinary barriers to unintended effects from gene research groups that bring together synthetic drive research might be geographical or biologists, ecologists, evolutionary biologists, ecological confinement, with the use of environmental scientists and social scientists offshore laboratories or offshore field trials. amongst others, to examine potential risks In the case of the malaria gene drive work, from the outset. These approaches are well the initial research is being conducted in the exemplified by Target Malaria, a not-for-profit UK in contained laboratories with Anopheles research consortium that aims to develop gambiae mosquitoes12. In the unlikely event of and share technology for malaria control. The escape from the laboratory, these mosquitoes consortium includes scientists, stakeholder should not be able to survive due to the cool engagement teams, risk assessment specialists climate and there is no native wild population and regulatory experts from Africa, North with which they could mate. In addition, America and Europe10. experiments being considered in Australia to explore the use of gene drives to control 9. Op. cit. note 5. 10. targetmalaria.org/who-we-are/ (Retrieved 12/10/2018). 11. Op. cit. note 5. 12. Op. cit. note 5. 6 GENE DRIVE RESEARCH: WHY IT MATTERS invasive rodent species would be conducted RECOMMENDATION on islands. Assuming the satisfactory Given the potential benefits of gene drives, completion of geographically or ecologically it is important that research to develop this confined trials, it will also be necessary technology continues. It is equally important to conduct field trials in intended release that research assessing the risks of releasing locations before any non-experimental gene drive organisms into the environment releases in those areas. The extent to which a continues in parallel. Any future use of gene particular location provides safe and effective drives should be preceded by public debate containment will need to be assessed on a about the relative desirability of using gene case-by-case basis. drives compared with alternative social, economic or technological solutions. Given Once a gene drive is released, potential the early stage nature of much of this work, containment mechanisms include limiting the any move to prohibit research into gene number of generations over which the gene drives would stifle this debate without a clear 13 drive operates in order to partially contain it , understanding of what the technology can do or developing a drive for a DNA sequence and whether it can be used safely. The Royal that is specific to the target population. It may Society therefore recommends that the UN also be possible to release a ‘reversal drive’ Convention on Biological Diversity avoid the or other engineered trait which can remove adoption of any position that would support 14 the initially introduced trait . an international moratorium on gene drive research, including experimental field trials. 13. Noble, C., Min, J., Loejarz, J., Buchthal, J., Chavez, A., Smidler, A.L., DeBeedictis, E.A., Church, G.M., Nowak, M.A., Esvelt, K.M. 2016. Daisy-chain gene drives for the alteration of local populations. BioRxiv. 14. Oye, J., Esvelt, K., Appleton, E., Catteruccia, F., Church, G., Kuiken, T., Lightfoot, S.B.Y., McNamara, J., Smidler, A., Collins, J.P. 2014. Regulating gene drives. Science. 345(6197): 626 – 628 GENE DRIVE RESEARCH: WHY IT MATTERS 7 Gene drive questions and answers 8 GENE DRIVE RESEARCH: WHY IT MATTERS QUESTION ONE What are gene drives? Gene drives are systems that bias the Figure 2 demonstrates the difference between inheritance of a particular DNA sequence. the usual pattern of genetic inheritance They can be used to increase the persistence (known as Mendelian inheritance after Gregor of an introduced trait that would otherwise Mendel who identified it) and inheritance disappear from a population very rapidly under a gene drive that has been designed to because the introduced trait puts the spread at the maximum possible rate through organism at a disadvantage. They can also a population, known as a ‘homing
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