TWN Info Service on Biosafety
7 February 2022
Third World Network
www.twn.my
Dear Friends and Colleagues
Case Study on the Ecological Impacts of Gene Drives Raises Concerns
Gene drives aim to modify or suppress wild populations of animals or plants by spreading genes or a genetic modification within a population at a super-Mendelian rate. Because of the potential risk of uncontrolled spread of gene drive organisms, a prospective analysis should not limit itself to the geographical boundaries of the targeted population for gene drive deployment. Instead, it should have a broader perspective and consider the species as an integral part of the environment, with all the interactions that it has across all potential ecosystems.
This case study presents an approach of prospective ecological vulnerability analysis for the proposed control of the invasive pest, Spotted Wing Drosophila (SWD) (Drosophila suzukii), by using gene drives. The analysis considers the accidental spread of the gene drive to the native habitat of SWD, with a focus on Japan. Multiple cascading effects were identified including the potential spread of the gene drive in geographic range or potential hybridization with non-target species. A high vulnerability was obtained for the suppression of non-target (native) populations of SWD as well as for a decrease in specialized parasitoid abundance.
The paper proposes the outline of a comprehensive prospective approach to understand the susceptibility of an ecosystem to unintended and irreversible harm. While more information is needed to make more precise predictions about the potential adverse impacts a gene drive might have if it is released for SWD, given there are some reasons for concern, the authors recommend that the precautionary principle should be applied.
With best wishes,
Third World Network
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ECOLOGICAL VULNERABILITY ANALYSIS FOR SUPPRESSION OF DROSOPHILA SUZUKII BY GENE DRIVES
Lalyer, C. R., Sigsgaard, L., & Giese, B.
Global Ecology and Conservation, e01883.
https://doi.org/10.1016/j.gecco.2021.e01883 https://www.sciencedirect.com/science/article/pii/S2351989421004339
December 2021
Highlights
• Hazard impact maps help determine cascading effects of an ecosystem perturbation.
• Vulnerability analysis is used to indicate the effects of a gene drive application.
• Reasons for concern and knowledge gaps uncovered following gene drive releases.
Abstract
Synthetic gene drives are transgenic constructs that aim to bias heredity and thereby influence the characteristics and fate of populations regarding abundance and evolution. Aside from irreversible effects in ecosystems that could be triggered by the release of a gene drive, research on confinable drives or even the reversibility of gene drives is underway and shows first success under laboratory conditions. However, their effectiveness under realistic conditions is not entirely clear unless first test releases have taken place. Since a potentially irreversible intervention into ecosystems is created, a prospective assessment is needed. We present an approach of prospective ecological vulnerability analysis for the proposed control of the invasive pest Drosophila suzukii by using gene drives. The analysis considers the accidental spread of the gene drive to the native habitat of Drosophila suzukii, with a focus on Japan. It contains a mapping of potential impacts as a consequence of the suppression of the insect. Multiple cascading effects were identified including the potential spread of the gene drive in geographic range or potential hybridization with non-target species. Determining the vulnerability of an ecosystem requires information regarding specific characteristics at different organizational levels. The vulnerability analysis of an affected ecosystem will initially serve to identify gaps in knowledge. Reducing complexity and breaking down the potential events that might arise from a gene drive population suppression enables to better understand endpoints i.e. concrete effects. Three potential effects have been selected for a specific analysis of the vulnerability of populations and species. A high vulnerability was obtained for the suppression of non-target (native) populations of Drosophila suzukii as well as for a decrease in specialized parasitoid abundance. The paper proposes the outline of a comprehensive prospective approach to understand the susceptibility of an ecosystem to unintended and irreversible harm.