Gene drives – technologies for propagating genetic modifications throughout populations
Gene drives are genetic elements or genetically engineered DNA constructs the inherent properties of which ensure that they are passed on disproportionally often by inheritance (i. e. with a frequency of more than 50 % for a certain gene variant of paternal or maternal origin). Thus, the traits determined by such genetic elements can spread preferentially and rapidly in populations (and potentially allow even the genetic modification of entire wild populations or species). Gene drives have been known as a natural phenomenon for a long time already. But only since the rapid development of genome editing (using the CRISPR/Cas system) as of 2012 and the resulting possibilities for the production of synthetic gene drive systems, they have become a main focus of more intensive scientific activities. Since 2014, they have also been the subject of bioethical, regulatory and research policy analyses.
The development of gene drives and gene drive technologies aims at spreading a desired, genetic trait throughout a population of living organisms. Frequently cited research and application objectives include the decimation (to the point of total extinction) of invasive species (to protect natural ecosystems in affected areas) or of insect populations that either damage agricultural crops (such as the olive or Mediterranean fruit fly) or transmit human pathogens (such as the Anopheles mosquito for malaria or the Aedes mosquito for dengue fever). Alternatively, gene drives could also be used for modifying disease-transmitting insects (or insect populations) in such a way that pathogens (e. g. for malaria) can no longer be transmitted (efficiently).
Compared to previous applications or application scenarios of genetically modified organisms (GMOs) in agriculture or in the combat against the spread of diseases, the mode of action of gene drives represents a kind of paradigm shift: In already existing approaches, genetic modification shall be limited to the released GMOs (e. g. in case of genetically modified crops in agricultural cultivation systems) or the reproduction and propagation of the released GMOs shall be prevented by self-limiting systems (in case of so-called sterile insect technology approaches for reducing insect populations). In contrast, gene drives explicitly aim at propagating the GMOs or genetic modifications in the population of the same species that has not yet been modified. This has fundamental consequences with regard to risk assessment and possible risk management measures of gene drive applications, but also regarding issues linked to risk-benefit analysis serving as a basis for a possible authorisation of experimental releases.
Objectives and approach
The TAB project is intended to provide an overview of the current status of gene drive technologies and their potential applications, to examine essential risk dimensions and to work out options for action – in particular with regard to regulation and research strategies. The project will focus on the following questions:
- For which areas is an application of gene drives being discussed? To what extent are gene drives suitable for solving problems? Are effective »locally acting« gene drive systems a possible option? What alternatives exist?
- What are possible ecological consequences? Which biological safety measures are being discussed? Which central aspects must be included in risk assessment? How can it be put into relation with benefit assessment?
- What ethical questions and dimensions have to be dealt with regarding such far-reaching interventions in wild populations? What are the criteria for an ethically and socially sound basis for decision-making regarding the question whether and, if so, where gene drives should be used?
- What risks of misuse by military applications or terrorism exist (e. g. in the context of bioweapons)? What is the resulting need for regulation at the national and international level?
- Which approaches regarding regulation and damage prevention are being discussed? Which structures, institutions and international regimes are playing a role in this context or are suitable for regulation? What are the most urgent regulatory steps?
The novelty and complexity of gene drive technologies and their ethical, regulatory and societal implications require a particularly thorough analysis. As a starting point, the TA project will present an inventory of scientific-technical developments and possibilities, envisaged applications and alternative problem-solving strategies. Then, based on selected representative examples from various potential fields of application, a comparative ecological and ethical impact analysis will be carried out. Moreover, the international regulatory debate will be recapitulated in detail and analysed with regard to its possible consequences for German policy.
In June 2020, the German Bundestag commissioned three expert reports on possible applications of gene drives in comparison with alternative approaches in the fields of health, agriculture and environmental protection and nature conservation, which have since been evaluated. Another expert study to analyze the public and scientific discourse on gene drives was commissioned by the German Bundestag in September 2021 and is currently being prepared.