Sterile hybrids between two species dumbfounded Darwin: how could natural selection create traits that could not be passed on from parent to offspring! A simple solution appeared with the formulation of the Biological Species Concept, that shifted the focus from adaptive traits to barriers to reproduction. However, this created a disconnect between ecological and genetic studies of speciation that still persist today. On one hand, many reproductive barriers, like hybrid sterility, are interpreted with models were genetic drift, sexual selection, and various forms of selection all produce similar patterns. On the other hand, ecological studies focus largely on early stages of divergence where local adaptation and reproductive isolation are one and the same but divergence can be reversed. Here, I discuss this historical decoupling and show how work in my laboratory is helping us bridge this gap by explaining how natural selection drives the evolution of traits and reproductive isolation at different stages of population divergence. I highlight novel results on the genetic basis of architectural differences between coastal populations of the Senecio lautus species complex, and discuss interpretations for patterns of intrinsic reproductive isolation across half-million years of divergence in Senecio. We might have theoretical solutions for Darwin’s mysteries, but the jury is still out on the evidence, so, like Darwin, we remain dumbfounded!
Daniel is an Associate Professor in evolutionary genetics at The University of Queensland. He got his PhD from Louisiana University in 2005 under the supervision of Professor Mohamed Noor, and then went onto do a postdoc with Professor Loren Rieseberg at UBC. He joined UQ as a Lecturer in October 2007. His research focuses on understanding the genetics and ecology of speciation. He has done speciation research in Drosophila, sunflowers, and more recently in a new system he has developed his laboratory, the Senecio lautus species complex.