Convergent evolution of hybrid inviability in Drosophila. Daniel R. Matute¹, Jackie Gavin-Smyth². 1) Human Genetics, Univ Chicago, Chicago, IL; 2) Ecology and Evolution, Univ Chicago, Chicago, IL.

   Postzygotic isolation causes reduced gene flow between species after the zygote gets formed, for instance by causing hybrid inviability or sterility. Dissecting the genetic basis of hybrid inviability not only reveals the role of molecular evolution in keeping species distinct, but also sheds light on coevolution required for genes to interact normally in pure species. Using high-resolution mapping we found that dorso-ventral specification is prone to breakage in two different hybrids (D. melanogaster/D. santomea and D. melanogaster/D. sechellia) and that two specific genes (dl and fog) lead to hybrid inviability in these two interspecific hybrids. These results demonstrate that the independent evolution of a developmental trait in two lineages involved changes to the same molecular mechanisms and that postzygotic isolation can have the same genetic basis in different interspecific hybrids.