Researchers identified a gene that drives sex determination in mosquitoes, and the finding could help fight dengue fever.

Only female mosquitoes bite and spread disease among humans, so a higher proportion of males could help reduce mosquito-borne infections, Virginia Tech reported. A team of researchers pinpointed a genetic switch, called Nix, in Aedes aegypti mosquito that holds the key to the difference between males and females.

"Nix provides us with exciting opportunities to harness mosquito sex in the fight against infectious diseases because maleness is the ultimate disease-refractory trait," said Zhijian Jake Tu, a professor of biochemistry in the College of Agriculture and Life Sciences and a Fralin Life Science Institute affiliate.

The researchers injected Nix into mosquito embryos, and found over two-thirds of the females developed male genitalia. When Nix was removed through a genome-editing method known as CRISPR-Cas9, male mosquitoes developed female genitalia. The researchers hope this discovery will lead to a new way to reduce or eliminate disease-spreading females from mosquito populations.

"We're not there yet, but the ultimate goal is to be able to establish transgenic lines that express Nix in genetic females to convert them to harmless males," said Zach Adelman, an associate professor of entomology in the College of Agriculture and Life Sciences and a Fralin Life Science affiliate.

Aedes aegypti is an invasive species that originated in Africa, it can spread disease and is highly adaptable to a wide range of environments. 

"Targeted reduction of Aedes aegypti populations in areas where they are non-native could have little environmental impact, and drastically improve human health," said Brantley Hall, a Ph.D. student and co-first author on the paper.

The findings were published in a recent edition of the journal Science Express.