“Target species complex” concept: Strengthening environmental risk assessment of engineered gene drives
“Target species complex” concept: Strengthening environmental risk assessment of engineered gene drives
Tags: Genetic engineering, Mosquitoes, Risk and safety, Risk assessmentJ.B. Connolly, Y. Devos, D.C.M. Glandorf, and J. Romeis, Proc. Natl. Acad. Sci., 2026.
The recent opinion piece of Christophe Boëte critiqued the concept of the target species complex (TSC) in environmental risk assessment (ERA) of engineered gene drives (EGDs) (1). While constructive debate is essential, the piece misrepresents the purpose of TSC and conflates unrelated mechanisms, creating misconceptions that merit clarification. Malaria-transmitting mosquitoes often belong to species complexes, comprising vector and nonvector species, where hybridization can be detected in laboratory settings and occasionally in the field (2–4). Low-threshold EGDs are self-sustaining and nonlocalizing (5). Should such EGD be released in a species complex where target genomic sequences are conserved, in the event of interspecific mating in the field vertical gene drive transfer (VGDT) to nonvector species could occur, potentially harming biodiversity protection goals. Conversely, VGDT to vector species could advance health objectives (6).
