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Flies and mosquitoes: A comparative analysis of distant relatives
  
By
Edward R. Winstead


 

Scientists are using the fly genome sequence to study an African mosquito that transmits malaria. The two insects are not closely related—the species diverged from a common ancestor some 250 million years ago; and the mosquito's genome is uncharted territory compared to the fly's, which was sequenced in 2000. A comparative analysis of the species' DNA revealed that there was less shared sequence than expected between the organisms.


Anopheles gambiae: adult female bloodfeeding on human skin

The study "illustrates how full genomic information from a model species can help provide considerable insight into the genomic structure" of a distantly related and little-studied organism, the researchers write in Genome Research. The comparison of sequence data was possible because in recent years thousands of DNA sequences for mosquito genes (or fragments of genes) have been deposited in computer databases.

Christos Louis, of the University of Crete, in Greece, led the comparison of Drosophila and the main African malaria mosquito, Anopheles gambiae s.s. (sensu stricto). The order of genes along the insect chromosomes has been "extensively reshuffled" during evolution, but the researchers detected regions both genomes had in common, including 113 pairs of genes that appear to be related.

The study used statistical tools to identify matches between genes in both species, and the criteria were relatively strict because the goal was to identify clearly related genes. The fly genome is easily manipulated, and it can be used to test the functions of mosquito genes that are also present in flies. Researchers have used Drosophila in the same manner to study human genes for decades.

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Bolshakov, V.N. et al. A comparative genomic analysis of two distant diptera, the fruit fly, Drosophila melanogaster, and the malaria mosquito, Anopheles gambiae. Genome Res 12, 57-66 (January 2002).
 

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