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Source: BBC

Laboratory-bred mosquitoes carrying a ‘death gene’ that kills their offspring could help eliminate dengue fever.

The mosquitoes are in effect sterilised, using a genetic approach known as tetracycline-controlled transcriptional activation (tTA). The tTA gene is spliced into the insect's genome in such a way that the protein it makes increases the gene's activity, thus making more and more tTA protein. The cell’s capacity to make other essential proteins is depleted, eventually killing the insect.

This cycle is turned off in the bred insects, but the active tTA gene is passed to their wild-born offspring.

While the idea of mass release of sterile insects is not new, previous attempts have faltered as laboratory-bred males struggled to compete with their wild counterparts for females. The genetically modified (GM) mosquitoes seem to fare better. The GM males made up 16% of males in the study area, and fathered 10% of the larvae.

"We were really surprised how well they did" said Luke Alphey, chief scientific officer at Oxitec, the company carrying out the research: “You'll never get the males as competitive as the wild ones, but they don't have to be, they just have to be reasonably good".

The next step is to demonstrate that deploying GM males suppresses the insect population enough to reduce dengue incidence. If so, the sterile mosquitoes could form a significant part of an integrated anti-dengue programme.