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GM mosquitoes' wild success

Science | Health

Pete Wilton | 31 Oct 11

red and green GM mosquito larvae

Genetically modified male mosquitoes have been shown, for the first time, to mate successfully in the wild.

The experiment, carried out in the Cayman Islands and reported in Nature Biotechnology, shows that males, modified so that any offspring they father die before reproducing, could help to tackle outbreaks of dengue fever and other insect-borne diseases.

‘We were really surprised how well they did,’ Luke Alphey, a visiting professor at Oxford University and chief scientific officer of Oxford University spinout Oxitec, which developed the approach, told BBC News Online’s Jonathan Black.

‘For this method, you just need to get a reasonable proportion of the females to mate with GM males - 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 GM modified male Aedes aegypti mosquitoes made up 16% of the male population of the trial area and fathered 10% of larvae – close to the mating success rate of wild males and evidence the technique could work outside the lab.

Aedes aegypti is a target because it carries dengue fever – afflicting an estimated 100 million people each year with some countries seeing ‘explosive’ outbreaks.

Luke explains that bednets offer no protection against dengue because the female mosquitoes carrying the virus bite during daytime.

‘We don't advocate [GM mosquitoes] as a 'magic bullet' that will solve all dengue in one go,’ he adds, ‘so the question is how it fits in as part of an integrated programme - and for dengue, it would be a huge component of an integrated programme.’

The next stage is to see if the release of a group of GM males can have a significant impact on the number of cases of dengue.

Luke Alphey is a visiting professor at Oxford University’s Department of Zoology.

Image: GM larvae carry a fluorescent gene. Photo: Derric Nimmo/Oxitec.

Oxford University helped to fund the development of the approach through four awards from the Oxford University Challenge Seed Fund (UCSF). Oxitec was spun out of Oxford University by Isis Innovation in 2002.