Fruit Flies Show Adoptive Genetic Variation

According to Charles Langley, professor of genetics in the Department of Evolution and Ecology at UC Davis and an author on both papers, their work reveals strong evidence of pervasive natural selection throughout the D. Melanogaster genome. That is in striking contrast with what is known of the human genome, which shows comparatively little evidence of adaptation over the last 100,000 years.

This time the human geneticists are working to sequence a thousand human genomes to get at the same issue.

"Most of the theory and statistical methods in human genetics were originally motivated by studies of flies, because they're easier and faster to work with," Langley said. "Model organisms like these play a critical role in developing tools and ideas."

The first paper that was published Oct 1 in the journal Genetics, reports the genomes of 37 strains of Drosophila that was collected in Raleigh, N.C., and six strains from the sub-Saharan nation of Malawi. 

The other paper to be published in PloS Genetics and currently available online, describes the genomes of 139 fly strains covering 22 African and one European population.

Drosophila Melanogaster originated in Africa. The flies are thought to have appeared in Europe about 50,000 years ago, along with modern humans.  Over generations, different fly strains evolved quite specialized niches. But the African fly genomes show that just in the past couple of decades, flies similar to those found in Europe or the U.S. have established populations back in Africa, often in new environments such as urban and industrial developments.

But the African fly genomes show that just in the past couple of decades, flies similar to those found in Europe or the U.S. have established populations back in Africa, often in new environments such as urban and industrial developments.

"It may be that urbanization and development favor the more 'European' flies," Langley said.