Building the better bug.

TRANSGENIC INSECTS can be given new characteristics, as illustrated by these five Aedes aegypti mosquitoes. Normal individuals have what appear to be black eyes, the result of large amounts of red pigment. A mutant version of Ae. aegypti has white eyes because of the lack of an enzyme, kynurenine hydroxylase, required to synthesize the red pigment. This white-eyed condition can be altered via the insertion of the gene for the enzyme. The resultant mosquitoes produce enough pigment to have visibly pink eyes. Such eye-color changes merely point out the potential of transgenic technology for producing a strain incapable of transmitting yellow fever or dengue. A N TH O N Y A . J A M ES U n iv er si ty o f C al if or n ia , I rv in e