New Genetic Blueprint for Bloodsuckers

Third mosquito genome highlights pest’s adaptability.

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By Gwyneth Dickey, Science News

Scientists have produced a complete genetic blueprint of the southern house mosquito, one of the most widespread disease carriers of the mosquito family. It’s the third mosquito genome to be fully sequenced and may help scientists develop more effective pesticides against specific species and diseases.

“Now we have one representative of [each of] the three major groups of disease-carrying mosquitoes,” says study coauthor Peter Arensburger of the University of California, Riverside. Sequenced in 2002, the African Anopheles gambiae carries malaria. Aedes aegypti, sequenced in 2007, lives in subtropical and tropical regions and carries yellow and Dengue fevers.

Now an international team of scientists reports in the Oct. 1 Science the genome of Culex quinquefasciatus, which sucks blood from birds, livestock and humans in tropical and temperate regions worldwide. This mosquito can transmit West Nile virus, St. Louis encephalitis and worms that can lead to elephantiasis.

It turns out that Culex has more protein-coding genes than the other two main groups of disease-carrying mosquitoes, a possible reason Culex can adapt to more varied environments than the other two groups can, the researchers say. 

Many of those extra genes code for smell and taste receptors, which may explain how the bloodsucker can find and munch on a variety of hosts. Other genes are specific for immune functions and detoxification, and could show how the pest quickly adapts to withstand new pesticides.

Comparing the trio of genomes may enable scientists to target specific genes using pesticides, says Arensburger. “Instead of trying to develop pesticides that hit all mosquitoes, we can try to target something that’s much more specific to just one species."

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