Male-Determining Genetic Switch (IMAGE) Virginia Tech Caption Life scientists identified a male-determining switch called Nix in a dangerous type of mosquito. The discovery could help protect human health. Credit Alexander Wild Usage Restrictions With photo credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.