Why Russian and U.S. mosquitoes are so different

One of the species the researchers studied is C. pipiens, which can carry West Nile Virus, a disease that has no medications to treat it or vaccines to prevent it. (Credit: Volkmar Becher/Flickr)

When scientists compared the genomes of urban and suburban mosquitoes in Russia and the United States they found a suburban mosquito in the US has more in common with an urban mosquito in the US than it does with a suburban mosquito in Russia.

That findings suggest individual populations are likely to have evolved resistance to whatever local selection pressures are typical in their area.

Understanding the genomes of those populations could one day help inform agencies about which pesticides are likely to be most effective against them.

“Mosquitoes adapt to heat, lifestyle, pesticides, and so on—and we see traces of that in their genome,” says Sergey Nuzhdin, a professor at the University of Southern California and corresponding author of the study, published in the Proceedings of the Royal Society B.

For the study, scientists tracked the which genes were evolving the fastest in two different but related species—Culex pipiens and Culex torrentium—by noting which genes were preserved most accurately in each genome.

Genes are subject to various copying errors. If there are a lot of variations throughout a population of a specific gene, then it probably isn’t crucial to their survival. If, however, all members of a population have a near perfect copy of a given gene, then there’s a good chance that natural selection is acting on it.


Based on which genes are being driven by evolution, the researchers found the widest variation between geographically separated populations than they did between populations in different types of environments.

“In addition to the insights into the contemporary evolution of mosquitoes, the methods we used in this study can be applied to compare genes under natural selection across populations of any species, including humans,” says Hosseinali Asgharian, lead author of the study and a PhD student at USC.

The research was a collaboration between USC, the University of California, Davis, and Moscow State University in Russia. The National Institutes of Health, and the Russian Science Ministry funded the work.

Source: USC