The new EU Biodiversity Strategy 2030 sets the ambitious target of halving the number of Red List species threatened by invasive species before 2030. However, current tools are insufficient to achieve this. Meanwhile, climate change is creating increasingly favourable conditions for the spread of various types of Asian tiger mosquitoes in Europe, bringing with it the potential risk of a greater incidence of mosquito-borne diseases, such as dengue, chikungunya and Zika.
In view of these conditions, leading scientists are calling on EU institutions to continue to back research into gene drive as a potential tool to protect public health and deliver on Europe’s biodiversity goals. Experts believe gene drive technologies could be a vital and effective solution in developing countries and islands, as well as across Europe.
On Thursday 29 October, researchers working on this technology will discuss the latest advances and the potential of gene drive technology with policymakers in an online event: Research and Innovation for biodiversity: what role for gene drive research?
In this interview, Austin Burt, a Professor of Evolutionary Genetics at Imperial College London and Principal Investigator of Target Malaria, answers some questions about his leading work on gene drive technology and his thoughts on the role of gene drive technology in the context of the EU’s Biodiversity Strategy 2030.
Firstly, could you please explain to our readers why gene drive technology matters? How do gene drives differ from conventional genetically modified crops or animals?
Whereas conventional genetic modification is directed at crops in fields or livestock or microbes in fermentation vats, all of which are situations in which we have a great deal of control over what we decide to plant, or which animals to breed, or which microbes to grow, gene drives are directed at species that we would like to control but are currently unable to such as vectors of disease, or invasive species causing extinctions.
Could you talk a little bit about Target Malaria, the project you are leading that intends to test gene-drive-carrying mosquitoes in sub-Saharan Africa?
Target Malaria is a not-for-profit research consortium trying to develop gene drive approaches to control the mosquitoes that transmit malaria, with a focus on sub-Saharan Africa, where the burden is highest. We believe that gene drive approaches have the potential to be highly effective, efficient, sustainable, and targeted interventions that can have a significant impact in reducing the very large burden of malaria in these areas.
Gene drives rapidly spread genetic modifications through animal populations and has the potential to alter entire species and wipe out diseases such as malaria, how might this also influence the surrounding environment and communities? What are the main risks and how can they be addressed?
There are many different kinds of gene drive, each with its own properties and each of which should be considered in its own right — some may well spread through and alter an entire species, but others would not. We do not believe that gene drive approaches can wipe out malaria by themselves, though in combination with other interventions (including bednets, etc), we agree that elimination is possible.
As for the effect on the environment and communities, again, this must be considered carefully on a case-by-case basis, as safety is paramount. A commonly expressed concern is that there may be some ramifying ecological effect through the food web.
Expert opinion suggests that is unlikely, as the mosquitoes that transmit malaria are not ‘keystone’ species in the community, and our experience with bednets also suggests there are unlikely to be large ramifying effects, but it is a question we are continuing to do research on, to further address this concern.
In 2018, a UN treaty agreed to limit gene drives but nations rejected an all-out moratorium. The document mainly outlines the risks of gene drive technology. What are the potential benefits?
The potential benefits of gene drives are the ability to address in a new way long-standing grand challenges that we have not been able to satisfactorily address with other methods. The two potential use cases attracting the most attention are the control of vector-borne diseases and the control of invasive species. For malaria control, gene drive would potentially be a cost-effective and efficient addition to existing tools that does not rely on human behaviour changes, while in conservation, a gene drive solution could offer a more humane way of controlling invasive species than the rodenticides and pesticides currently used.
What are the main challenges to overcome before the technology could be effectively and safely used? In addition, what safeguards are necessary to put in place to ensure responsible development?
To be clear, there is not a single technology being considered here — it is a suite of approaches that are being investigated, and what is appropriate for one species and location and objective will probably not be the same as what is appropriate for another species, location, and objective.
That said, the potential for resistance to evolve is a cross-cutting issue. Anytime one does anything to control a population, one must consider the potential for the evolution of resistance — that is true for conventional chemical control, and also for gene drive approaches. Moreover, very specific and detailed risk assessments must be performed, to evaluate and weigh up the risk:benefit ratio for any specific proposed case.
Is there variation in the stances of different research groups on the use of gene drives or is there a general consensus?
There are many different types of gene drive, and many ways they could be used to address unsolved challenges, and different research groups are investigating a large diversity of gene drive approaches. This diversity of approaches is very healthy for the field and bodes well that at least some groups will be able to develop truly transformative new tools.
Gene drives can also be used to rescue endangered populations, as well as to suppress or eradicate undesirable populations, such as a disease-carrying species. What are the potential implications for conservation biology and ecosystem management?
This possibility has received less attention and research than the other potential applications, but there is an enormous need to research and identify new conservation tools, as current technologies will be insufficient to meet conservation goals, including those set out in the EU’s Biodiversity Strategy. Among the groups working on this is the Genetic Biocontrol of Invasive Rodents (GBIRd) program.
As I understand, your work mainly focuses on implementing this technology in sub-Saharan Africa. How could this technology also help meet Europe’s biodiversity and public health goals? Are you involved in any of the work in this area (in Europe)? If so, would you mind telling our readers a little bit about it?
Climate change and the invasion of Aedes albopictus into southern continental Europe means there is an expanding risk of vector-borne disease such as dengue, and gene drive approaches ought to be investigated to see if they might help protect us from those diseases. There are also the tropical overseas territories of some countries which include Guyana and the Antilles, both of which have experienced outbreaks of Zika virus. There would also be a number of invasive species in Europe.
What will be the main agenda at the meeting with EU policymakers on Thursday? What are you hoping can be achieved/hopes for the future of gene drive technology in Europe? What are the main issues currently holding back the technology?
This is mostly an information-sharing meeting. For my own part, I want to emphasise that gene drives are not a single thing, but rather a suite of potential interventions — there is not even a precise, agreed-upon definition of gene drive — and therefore a case-by-case assessment of specific proposals is needed, not blanket declarations. Details matter, which is why it is so important for research to continue to provide answers to the questions around safety and efficacy.