What women want makes a difference

Males will court just about anything, but females mate preferentially with their own species. This, at least, is true for
two species of the fruitfly Drosophila (D pseudoobscura and D persimilis) that occur in the same environment along the
western United States and can interbreed where they meet. In the open-access journal PLoS Biology, Daniel Ortiz-Barrientos
and his colleagues present the first high-resolution analysis of "species reinforcement genes" that account for heightened
discrimination by females in populations faced with a choice, compared with their isolated peers.


The researchers identify two new loci that influence the likelihood that a female will choose to mate with a male of her own
species, rather than one of a closely related species. Because the daughters of discriminating D. pseudoobscura females were
just as discriminating as their mothers, they concluded that female mating discrimination is inherited as a dominant trait.
They further show that genes responsible for female preference are on the X and fourth chromosomes. The most promising genes
in both regions appear to be involved with olfaction and on this basis, the authors propose a novel model of speciation via
mating discrimination in Drosophila pseudoobscura based on the combined response to auditory and olfactory cues.


These findings mark a major turning point in the study of speciation as they provide vital clues to the final stages of the
speciation process. Ortiz-Barrientos and colleagues are now poised to identify and study the evolution of the actual genes
contributing to the creation of new species.


Citation: Ortiz-Barrientos D, Counterman B, Noor M (2004) The Genetics of Speciation by Reinforcement. PLoS Biol 2 (12):
e416.


CONTACT: Daniel Ortiz-Barrientos

Louisiana State University

107 Life Sciences Bldg

Baton Rouge, LA USA 70803 1-225-578-7081

1-225-578-2597 (fax)

dortiz1lsu


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