Closely related species may continue to interbreed, which can have a profound impact upon the course of their evolution. The aim of this project is to reveal the genetic changes that enable individuals to distinguish their own species at courtship and reproduction. Two species of fruit fly, Drosophila simulans and D. sechellia diverged ~250,000 years ago but will still hybridize with each other in the laboratory and in the wild. This new research tested the mating preference of 1,470 D. simulans-D. sechellia hybrid females, sequenced the genome of each individual fly, and used this information to construct a genetic map of their mate preferences. The research identified two genomic regions that had a major effect on between-species mate choice.
Redistribution of recently diverged species from their native range is a feature of globalization. We unexpectedly found that different allele combinations at the two major loci that we identified may promote hybridization as well as isolation in the same species pair; some genotypes of hybrid females promote mating within species while other genotypes facilitate hybridization between species. Identification of these loci will allow us to better predict the outcome of invasions.
Researcher Dr Deniz Erezyilmaz comments, ‘Our aim was to generate a high-precision map of mate choice in females that would describe affinity for mates of the same species. In the process we zeroed in on the genetic combinations that make hybridization likely.’
In conducting this research the work benefited from discussions with the entire Goodwin group. Input from Mike Ritchie at St. Andrews was also helpful in writing the manuscript. We are very grateful to David Stern, who conducted a portion of the computational analysis at Janelia Farm. This work was supported by Stony Brook University start-up funds, National Environmental Research Council Grant to Stephen Goodwin. Deniz Erezyilmaz was supported in part by an American Association of University Women Postdoctoral Leave Fellowship.
Read the paper here