Tamed. Researchers have genetically modified Anopheles gambiae mosquitoes for the first time
BARCELONA -. Motivated by more than one million deaths from malaria each year, scientists have fantasized about the ultimate method of eradication: replacing existing populations of mosquitoes incapable of spreading the disease. Two advances reported at the Third International Congress of Vector Ecology here on 20 September may help edge that dream closer to reality
Putting all new gene into mosquitoes was difficult .; a technique used in Drosophila does not work. Last year, scientists at the European Molecular Biology Laboratory in Heidelberg, Germany, reported that they genetically modified Anopheles stephensi , a species that transmits malaria in India. The team inserted a test gene that encodes green fluorescent protein (GFP). But the gene does not cause resistance to Plasmodium , the parasite that causes malaria.
Now, a team led by Marcelo Jacobs-Lorena, a molecular entomologist at Case Western Reserve University in Cleveland, Ohio, is spliced in the same species of mosquito gene that. It encodes a peptide, called SM1, which appears to counteract Plasmodium by blocking receptors in the gut and salivary glands of mosquitoes. Without access to these receptors, Plasmodium can not replicate in the insect and infect humans when the mosquito bites. In carrying mosquitoes gene Plasmodium lost 85% to 95% of its ability to replicate, and the mice bitten by insects do get sick. In contrast, more than half the mice bitten by normal mosquitoes were infected.
Meanwhile, Mark Benedict Centers for Disease Control and Prevention (CDC) in Atlanta announced at the meeting that his team created the first transgenic Anopheles gambiae , malaria vector most prevalent in Africa. The team slipped GFP gene in A. gambiae as a first step. However, the realization is "very, very exciting," says Paul Eggleston of Keele University, UK. It is probably a matter of months before researchers produce a version of resistant malaria says Eggleston -. For example, by providing it with SM1
Skeptics warn that even such a feat would not mean the end of malaria; there are many obstacles, so that new mosquitoes replace existing ones to convince the public that it is safe to release them. But even if they are never released, says Eggleston, the altered mosquitoes will teach researchers about how malaria parasites interact with their host.
Related Sites
science story on the genetic modification of mosquitoes
CDC information on malaria
The homepage Paul Eggleston
The third International Congress of Vector Ecology
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