As a “proof of concept” of a new split gene-drive system developed by researchers at the University of California, Riverside, CRISPR/Cas9-mediated disruption of genes associated with cuticle pigment caused mosquitoes to turn from black to yellow, and disruption of genes associated with eye pigment caused eye color to change from black to white. The genetic modification was enabled by the researchers’ development of Aedes aegypti mosquitoes that have the Cas9 enzyme “built-in,” inherited from their parents and passed down to their offspring. (Photo credit: University of California, Riverside)