Field Trials of Gene Drive Mosquitoes: Lessons from Releases of Genetically Sterile Males and Wolbachia-infected Mosquitoes
Field Trials of Gene Drive Mosquitoes: Lessons from Releases of Genetically Sterile Males and Wolbachia-infected Mosquitoes
Tags: Field trials, Gene drive synthetic, Incompatible insect technique, Mosquitoes, Sterile insect technique (SIT), WolbachiaJ. M. Marshall and V. N. Vásquez, Genetically Modified and other Innovative Vector Control Technologies, 2021.
The discovery of CRISPR-based gene editing and its application to homing-based gene drive has been greeted with excitement, for its potential to control mosquito-borne diseases on a wide scale, and concern, for the invasiveness and potential irreversibility of a release. At the same time, CRISPR-based gene editing has enabled a range of self-limiting gene drive systems to be engineered with much greater ease, including (1) threshold-dependent systems, which tend to spread only when introduced above a certain threshold population frequency, and (2) temporally self-limiting systems, which display transient drive activity before being eliminated by virtue of a fitness cost. As these CRISPR-based gene drive systems are yet to be field-tested, plenty of open questions remain to be addressed, and insights can be gained from precedents set by field trials of other novel genetics-based and biological control systems, such as trials of Wolbachia-transfected mosquitoes, intended for either population replacement or suppression, and trials of genetically sterile male mosquitoes, either using the RIDL system (release of insects carrying a dominant lethal gene) or irradiation. We discuss lessons learned from these field trials and implications for a phased exploration of gene drive technology, including homing-based gene drive, chromosomal translocations, and split gene drive as a system potentially suitable for an intermediate release.