16 August, 2010

Malaria-proof mosquito engineered

The scientists tagged the gene with a fluorescent marker to ensure it had been inserted
Genetically engineering a malaria-resistant mosquito

The researchers, from the University of Arizona, have succeeded in genetically engineering a malaria-resistant mosquito by introducing a gene that affected the insect’s gut, meaning the malaria parasite could not develop. Although the ultimate goal was to introduce malaria-resistant mosquitoes into the environment, is also reduces the insects’ lifespan.

In the study the researchers altered a gene that codes for a “signalling molecule”.
This molecule, a protein, enables the mosquito’s cells to communicate with each other, and is crucial for parasite development inside the mosquito.

This is a key step in a long genetic battle against a global killer. The ultimate aim is to tackle the root cause of malaria’s spread by releasing the parasite-proof mosquitoes into the environment.

For that to be successful, the genetically modified insects would have to “take over” from the naturally occurring, disease-spreading mosquitoes.

This means giving the GM insects a competitive advantage – something that has not yet been achieved. Researchers are investigating a number of genetic “tricks” in pursuit of this.

One of these is to ensure that the gene that blocks the parasite’s development is guaranteed to be passed down to the modified mosquitoes’ offspring – thereby making sure that the gene eventually spreads throughout the population.

The other is to give the malaria-resistant mosquitoes an additional genetic boost, such as a gene that makes them resistant to toxins that could be used against unmodified mosquitoes.

But there are serious ethical concerns about releasing a genetically modified insect into the environment. Once the science is pinned down, the risks and benefits to the environment, and to human health, will have to be properly assessed.

The genetic tweak artificially increased its production, disrupting the whole process, and also shortened the insect’s lifespan.

The team was able to add a fluorescent tag to the gene, to ensure that it had been successfully “expressed” by the mosquito larvae.

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