One of the greatest unsolved questions in biology is how continuous processes of evolutionary change produce the discontinuous groups known as species. For a many years, my team studied hybrid sterility and behavioral mate preferences using classical, QTL-based, or molecular genetic approaches on Drosophila species as model organisms. More recently, the availability of multiple whole-genome sequences (some public but especially those we have obtained ourselves) has dramatically enhanced the scope of progress we make. A major question we've sought to address has been determining the genetic features and evolutionary processes that allow hybridizing species to persist, with particular interest in recombination and chromosomal inversions. In addition to questions in speciation, we are broadly interested in molecular evolution within species, again with a particular focus on the effects of recombination. See my lab web page for more information.