The mosquito experiment

OUR MOSQUITO PROJECT TAKES FLIGHT, reads an eye-catching billboard off U.S. 1 in the Florida Keys. Sponsored by the local mosquito-control board and U.K.-based biotech firm Oxitec, the ad promotes a contentious plan to release millions of genetically modified Aedes aegypti mosquitoes to test a new method of bioengineered pest control. The experiment, which began in late April, is the first such trial in the U.S. and has turned these islands into a battleground over science, government authority and humanity’s right to modify nature.

Oxitec’s  mosquitoes—which the U.S. Environmental Protection Agency (EPA) approved for use last year—are genetically modified to include a “self-limiting” gene that produces a fatal protein. The mosquitoes are raised in a laboratory and fed tetracycline, an antibiotic that prevents the added gene from activating. The mosquitoes’ eggs are then left to hatch in the wild, without the antibiotic. The gene kills immature egg-laying females—the only ones that bite. But the males reach maturity, mate with wild females and pass on their faulty gene. Then their female progeny die, causing a