01 May 2006

Malaria resistant mosquitoes

As the Science magazine reports, a group of scientists from the U of Minnesota, the Fred Hutchinson Cancer Research Center in Seattle, Washington, Princeton University, and the University of Bamako in Mali have discovered that the 22 out of 100 known pedigrees of Anopheles gambiae mosquitoes--Africa's most important malaria vector--are already resistant to Plasmodium falciparum, the malaria parasite.

The resistance comes, as reported, from a single cluster of genes:

They discovered that a small region on the 2L chromosome of A. gambiae played an all-important role. The Plasmodium Resistance Island, as they dubbed it, contains almost 1000 genes. Using several techniques to shake out genes of relevance, they pinpointed one gene, APL1, that appears to play a particularly important role; when its action was blocked using RNA interference, mosquitoes became vulnerable to infection. Still, other nearby genes may be involved as well, says lead author Kenneth Vernick of the University of Minnesota, St. Paul.
This discovery brings up possibilities of novel ways of dealing with the disease: since there is already a fungi that attacks predominantly malaria-infected mosquitoes, it is possible to try and eradicate only those mosquitoes that do not posses the resistant allele of the APL1 gene.

Let's just hope that we have not tapped into this opportunity in the middle of the evolutionary arms race between the Plasmodium and Anopheles and that there are no parasites out there that are already capable of getting around the natural defenses of the resistant mosquitoes.


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