Potential use of gene drive modified insects against disease vectors, agricultural pests and invasive species poses new challenges for risk assessment

Abstract

Potential use of gene drive modified insects against disease vectors, agricultural pests and invasive species poses new challenges for risk assessment, Critical Reviews in Biotechnology,

Gene drive in species complexes: defining target organisms

“…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]. This paradigm is typically applied in the qualitative ERA of GM plants, where, in general, there is a clear distinction between the organisms to be targeted, the TOs, and those that are not intended to be targeted, the NTOs.…”

“…In particular, there is considerable interest in harnessing gene drives to control mosquito species that are vectors of human diseases such as malaria (Box 1) [4,5].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]. This paradigm is typically applied in the qualitative ERA of GM plants, where, in general, there is a clear distinction between the organisms to be targeted, the TOs, and those that are not intended to be targeted, the NTOs.While engineered gene drives share many of the same considerations as other transgenes in GMOs, such as non-gene drive genetically modified mosquitoes (GMMs), they differ in that they are designed to spread, increase in frequency, and persist in target organisms of wild populations.…”

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

“…However, including non-vector species of a complex as part of the defined TO set exceeds the intention to specifically target vectors. Therefore, the definition of TO in ERA of gene drive in species complexes requires more nuanced consideration and further refinement than would be the case for more conventional GMO applications [ 7 , 32 ].…”

“…It has previously been recognized that protection goals outlined in legislation are often too broad to be directly applicable for environmental risk assessment [ 33 , 35 , 39 , 40 ]. Establishing operational protection goals for individual pathways to harm thus represents an important area for future development of ERA for gene drive approaches to malaria vector control [ 32 ].…”

“…For example, comparisons could be considered to assess whether the gene drive application is more or less harmful than other currently deployed malaria vector control measures, such as insecticide-based applications that are used to manage populations of wild-type mosquitoes in disease control programs [ 8 ]. Such interventions thus represent one level of comparator to gene drive applications, to inform ERA and contextualize risks [ 7 , 8 , 32 , 50 ].…”