October 1, 2010

Genome Of West Nile Mosquito Sequenced

Scientists announced on Thursday that they had successfully sequenced the genome of the Southern house mosquito--the species of insect most responsible for the transmission of diseases such as West Nile virus, encephalitis, and elephantiasis.

Writing in two separate papers published by the journal Science, a team of researchers from 39 universities in the United States and Europe reported that they had completely mapped the DNA of the Southern house mosquito, or Culex pipiens quinquefasciatus--all 18,000-plus sequences.

Furthermore, they also completed a detailed investigation of the mosquito's immune response to the diseases it carries, doing so by injecting subjects with the West Nile virus and then extracting genetic material that will help show how it reacts to such disease-causing agents.

"Culex pipiens quinquefasciatus is the most widely distributed mosquito in the world, and in terms of disease transmission to humans it's one of the three most important mosquito species," Stephen Higgs, a professor at the University of Texas Medical Branch at Galveston (UTMB) and co-author of one of the two papers, said in a statement. "This work gives us a terrific platform to improve our understanding of the dynamics of infection, which has to be done if we're going to find ways to interrupt disease transmission."

Previously, researchers were able to sequence the genomes of two other mosquito species, Aedes egypti and Anopheles gambiae. The former is responsible for spreading yellow fever and dengue fever, while the latter transmits malaria. Culex's genetic code is said to be more than 20-percent larger than Aedes egypti's, and some 52-percent bigger than that of Anopheles gambiae.

Now that the researchers have discovered the core genetic information of the Southern house mosquito, they will now turn their attention to using that information to improve treatment of the diseases that it spreads.

"With the genome decoded, we have the building blocks. We can also determine which building blocks the mosquito uses to combat a pathogen and which genes the pathogen avoids when evading the defenses of the mosquito," Boston College DeLuca Professor of Biology Marc A.T. Muskavitch, who helped complete both papers, said in a statement Thursday.

"Our goal is to determine how we can turn the building blocks of these mosquitoes against pathogens, in attempts to defeat those pathogens," he added. "That is the scientific and public health significance of this new research."


Image Caption:  This image shows Culex quinquefasciatus, a representative of the Culex genus of mosquitoes. Credit: Jim Gathany/Center for Disease Control and Prevention


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