New tool for combating mosquito-borne disease: Insect parasite genes

Wolbachia is the most successful parasite the world has ever known. You've never heard of it because it only infects bugs: millions upon millions of species of insects, spiders, centipedes and other arthropods all around the globe. 

The secret to the over-achieving bacterium's success is its ability to hijack its hosts' reproduction. Biologists have known that Wolbachia have had this power for more than 40 years but only now have teams of biologists from Vanderbilt and Yale Universities identified the specific genes that confer this remarkable capability.

The two universities have applied for a patent on the potential use of these genes to genetically engineer either the bacterial parasite or the insects themselves to produce more effective methods for controlling the spread of insect-borne diseases like dengue and Zika and for reducing the ravages of agricultural pests.

"We've known for decades that one of the secrets to Wolbachia's success is that it interferes with host reproduction in order to spread itself through females. But how the bacterium did it was a major mystery for the field," said Associate Professor of Biological Sciences Seth Bordenstein, who headed the Vanderbilt contingent. "Now we know the genes that give it this capability."

Wolbachia commonly manipulates its hosts' reproduction by a process called "cytoplasmic incompatibility" or CI. This makes the sperm of infected males lethal to the eggs of uninfected females. The researchers have identified a single pair of Wolbachia genes that produce this effect only when working together.