US scientists have created a malaria-resistant, genetically-modified (GM) mosquito which they hope might displace its infectious counterpart if introduced into the wild.

According to the BBC, the transgenic Anopheles mozzie - which boasts a gene that resists infection by the Plasmodium malaria parasite - is "better able to survive than disease-carrying insects". The scientists let loose equal numbers of GM and common-or-garden mosquitos on malaria-infected mice, and after nine generations of reproduction "70 per cent of the insects belonged to the malaria-resistant strain".

Simply put, the GM insects "had a higher survival rate and laid more eggs". Dr Mauro Marrelli and his colleagues from Johns Hopkins University in Baltimore, explained in Proceedings of the National Academy of Sciences: "To our knowledge, no one has previously reported a demonstration that transgenic mosquitoes can exhibit a fitness advantage over non-transgenics."

They added: "The results have important implications for implementation of malaria control by means of genetic modification of mosquitoes."

It's not quite that simple, though. Survival rates for GM and non-GM mosquitos were the same when exposed to a non-infected food source. As the BBC explains, "for resistant mosquitoes to be useful in the wild, they must survive better than non-resistant mosquitoes even when not exposed to malaria".

The John Hopkins team's mosquitos boast one additional crowd-pleasing characteristic - fluorescent eyes, courtesy of the now pretty well obligatory green fluorescent protein gene. This feature is not, however, simply to create the entomological equivalent of the glow-in-the-dark pig, but rather to allow the scientists to better identify their offspring. ®

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