Gene drive

A gene drive is a natural process and technology of genetic engineering that propagates a particular suite of genes throughout a population by altering the probability that a specific allele will be transmitted to offspring (instead of the Mendelian 50% probability). Gene drives can arise through a variety of mechanisms. They have been proposed to provide an effective means of genetically modifying specific populations and entire species. The technique can employ adding, deleting, disrupting, or modifying genes. Proposed applications include exterminating insects that carry pathogens (notably mosquitoes that transmit malaria, dengue, and zika pathogens), controlling invasive species, or eliminating herbicide or pesticide resistance. As with any potentially powerful technique, gene drives can be misused in a variety of ways or induce unintended consequences. For example, a gene drive intended to affect only a local population might spread across an entire species. Gene drives that eradicate populations of invasive species in their non-native habitats may have consequences for the population of the species as a whole, even in its native habitat. Any accidental return of individuals of the species to its original habitats, through natural migration, environmental disruption (storms, floods, etc.), accidental human transportation, or purposeful relocation, could unintentionally drive the species to extinction if the relocated individuals carried harmful gene drives. Gene drives can be built from many naturally occurring selfish genetic elements that use a variety of molecular mechanisms. These naturally occurring mechanisms induce similar segregation distortion in the wild, arising when alleles evolve molecular mechanisms that give them a transmission chance greater than the normal 50%. Most gene drives have been developed in insects, notably mosquitoes, as a way to control insect-borne pathogens. Recent developments designed gene drives directly in viruses, notably herpesviruses.