Recommendations for environmental risk assessment of gene drive applications for malaria vector control

Abstract

Building on an exercise that identified potential harms from simulated investigational releases of a population suppression gene drive for malaria vector control, a series of online workshops identified nine recommendations to advance future environmental risk assessment of gene drive applications.

Gene drive in species complexes: defining target organisms

“…Owing to the inherent potential for hybridisation, increase in frequency and, thus, VGDT amongst species within complexes, more nuanced considerations and flexibility on the definition of TO is required for the ERA of gene drive mosquitoes belonging to species complexes than for other GMO applications [13]. In particular, defining the TO is complicated by the potential for VGDT of a gene drive from the original organisms released into the environment to other vector and nonvector species of the complex.…”

“…Likewise, environmental releases of GMMs resulting in substantial population suppression of Aedes aegypti (Diptera: Culicidae) populations in the Cayman Islands, Brazil, and Panama provide potentially analogous examples to the population suppression gene drive described here [45][46][47]. However, this GMO is a self-limiting strain in which there is no engineered gene drive particular event; the use of Bayesian networks can ensure that the input and output will be categorical so that risk can be defined both numerically and by a discrete number of categories [13]. Protection goals: policy, legislation, and stakeholder input defining environmental or health resources to be protected, the degree of protection they deserve, or the maximum impacts that should be tolerated.…”

“…Before any environmental release of an engineered gene drive mosquito could be considered by regulators, decision-makers and stakeholders, environmental risk assessment (ERA), whether probabilistic, qualitative, or a combination thereof, must be conducted to evaluate potential risks to human health, animal health and the environment [6][7][8][9][10][11][12][13]. A prerequisite for effective ERA of genetically modified organisms (GMOs) is to define intended and unintended effects of the intervention on target organisms (TOs) and nontarget organisms (NTOs) [9,10,[14][15][16][17].…”

“…Protection goals: policy, legislation, and stakeholder input defining environmental or health resources to be protected, the degree of protection they deserve, or the maximum impacts that should be tolerated. Qualitative ERA: defines, in a structured and systematic way, the likelihood and consequences of outcomes into a limited number of ordered classes to yield categorical indications of relative risk, such as high, moderate, low, or negligible [13]; approach used in most jurisdictions to evaluate risks from environmental release of GMOs [67]. Sibling species: species that are members of the same species complex.…”

“…It should be made clear that movement of the construct to sibling species that also are malaria vectors is considered part of the intended effect, and in that case functionality with respect to population suppression or replacement should be monitored in those other species. Indeed, in a recent series of recommendations on advancing ERA for gene drive applications, Connolly and colleagues recommended that the definition of the term TO for gene drive in species complexes required more nuanced consideration than for other GMO applications [13].…”