Genome-editing technologies in animals

CRISPR-Cas9 is often described as a “pair of molecular scissors” because it introduces highly targeted genome mutations. Its precision is far superior to that of classical genetics techniques or random mutagenesis.

Farm animal breeding

We can use genome editing to better understand genes and to enhance the traits of terrestrial and aquatic farm animals. Many potential applications exist, such as improving animal welfare and performance, boosting disease resistance, and helping animals cope with agricultural conditions. Additionally, genome editing can be deployed to reduce the environmental impacts of animal farming. The ethics committee underscores that these new techniques are a natural extension of animal domestication: we have long been artificially breeding animals for specific traits. The committee also notes that the intensification of animal farming over the last 50 years has resulted in conditions causing pain, suffering, and distress to animals. There is thus an ethical obligation to ensure animal welfare in breeding programmes, regardless of the techniques used. Potential applications must be evaluated on a case-by-case basis, given the specific trade-offs among animal productivity, animal welfare, and the preservation of natural animal behaviour. Consumer sensitivity may also differ depending on the issue. The ethics committee considers that genome-editing applications in animals can only achieve social relevance and public support if preliminary consensus on issues of concern is established via concerted discussion among diverse stakeholders. This position was shaped by the controversy provoked when genetically modified plants were developed and commercialised. In the case of aquatic farm animals, the committee particularly notes that genetically modified escapees could threaten the health and diversity of wild fish stocks. Thus, to promote social relevance and public support, INRA, CIRAD, and IFREMER must foster general awareness of this debate through clear communication and the dissemination of high-quality information. Under EU law, animals and animal products resulting from genome editing are defined as genetically modified organisms (GMOs). As such, they cannot be commercialised.

Controlling parasites, pests, and invasive species

The idea is sometimes raised that control efforts could be enhanced by introducing deleterious traits into insect pests, parasites, and/or disease vectors (e.g., mosquitoes). For example, by causing sterility or mortality, it would be possible to eliminate local populations or entire species. Another possibility would be to suppress direct or indirect pathogenicity. “Gene drives” can transform this idea into action. They are systems that almost guarantee a gene will be transmitted via sexual reproduction. Targeted mutagenesis techniques are a rapid way to implement gene drives. The use of gene drives has also been considered in the fight against invasive species (e.g., rats, opossums, stray cats) that present a threat to native flora or fauna. They are thus viewed as a strategy for controlling undesirable animals and insects. The ethics committee invites reflection on how gene drives contribute to such control efforts, as well as on how we feel and behave towards these species. As with any ethical dilemma, societies face a trade-off among multiple types of positive and negative consequences. Gene drives may seem to be a greener and more reliable alternative to chemical control. They certainly appear to serve the same function as the autocidal methods used in biological control. However, the potential reversibility of any adverse effects must also be considered. Ecological risks need to be analysed on a case-by-case basis. Some key questions include the following: How would this species’ disappearance affect the food chain? What are the risks of species extinction? What are the risks of another species proliferating? It is also important to consider whether pathogens of concern could be transmitted from one species to another. Within a given area, populations interact in dynamic ways. Indeed, what humans consider to be harmful may actually benefit the broader environment, upon which humans also ultimately depend. In such situations, the optimal solution is to focus not on human interests, but rather on the interests of the entire ecosystem, whose integrity affects humanity’s future.

Recommendations

Given the important concerns raised, including those of a philosophical and ethical nature, the ethics committee recommends caution when using genome-editing techniques in animals. It underscores that placing limits on this work is particularly difficult. A list of recommendations was issued to INRA, CIRAD, and IFREMER relating to the following topics:

• the use of genome-editing techniques to create knowledge and further research
• the importance of establishing priorities
• considerations related to animal welfare
• the need for additional research on gene drives
• responses to societal demands for information