Genetically modified mosquitoes are developed using genetic engineering. Gene drive-modified mosquitoes are a type of genetically modified-mosquitoes. In both cases, mosquitoes of the targeted species are modified to exhibit one or more different traits from wild type (non-modified) mosquitoes of the same species. An example of a desirable new trait would be a decreased ability of the modified mosquitoes to transmit diseases such as malaria or dengue. Modifications might involve altering the sequence of existing genes, disabling or excising of existing genes, or introducing new genes or other genetic elements within the mosquito genome.
Several genetic modification approaches are being explored, from those that will have no lasting effect on the targeted vector population after release to those that are intended to introduce a more persistent change. When not coupled to a gene drive, a gene (including any introduced genetic modification) is typically transmitted to the progeny from mating of modified with wild type mosquitoes according to the standard (Mendelian) pattern of inheritance, where each gene has a 50% chance of being passed from the parent to the next generation. If the gene or genetic modification is associated with a fitness cost (reduced competitive ability), the related trait is expected to disappear from the population over time. If the fitness cost is severe, the introduced gene(s) can disappear rapidly; this would be the case, for example, if the modification caused reduced fertility in those mosquitoes that carried it.
When coupled with a gene drive, the genetic modification is inherited preferentially. The related new trait will eventually become dominant in the population because more than 50% (sometimes almost 100%) of the progeny from matings between gene drive-modified mosquitoes and their wild-type counterparts inherit the modification.
For more information: https://www.geneconvenevi.org/gene-drive-defined/