A mosquito experiment mishap?
Genetically modified mosquitoes that were released in Brazil with the aim of reducing wild populations may have made the disease-bearing pests more “robust,” according to new research. From 2013 to 2015, biotech company Oxitec introduced hundreds of thousands of genetically tweaked mosquitoes—engineered to produce offspring that wouldn’t make it to adulthood—into the city of Jacobina. Overall mosquito numbers declined during the trial period. But a new study by researchers from Yale University found that the population started to rebound after 18 months. More troubling, the genomes of the modified insects showed up in wild mosquitoes. “The claim was that genes from the release strain would not get into the general population because offspring would die,” senior author Jeffrey Powell tells The Scientist. “That obviously was not what happened.” Powell and his team speculate that the added genetic diversity could result “in a more robust population.” Oxitec says the Yale study contains “false” and “unsubstantiated” claims and has called for a retraction. The controversy could deter local communities from giving the green light to future open-field trials. ■