This project is awarded under the Minority Postdoctoral Research Fellowships and Supporting Activities Program for 2006. Speciation is the process that ultimately leads to the diversity of life on the planet, and most definitions of species depend on the existence of reproductive barriers between populations. Empirical and theoretical work have shown that both divergence due to selection and due to random genetic drift could promote the evolution of reproductive isolation, but few empirical studies have looked for effects of these alternate forms of divergence in systems where divergence due to selection and divergence due to drift had occurred. Therefore we do not know if new species evolve because populations are adapted to different environments or because genes that cause reproductive isolation have drifted to fixation by chance. A direct test of the relative importance of drift and selection on reproductive isolation requires that the effects of these modes of divergence be measured in a system where both have promoted divergence. Working with Dr. Charles Fenster at the University of Maryland and by taking advantage of genetic and ecological resources that have become available for A. thaliana, I will test hypotheses that drift and divergent selection drive the evolution of reproductive isolation. I will use a combination of techniques from field work to collection of previously published estimates of genetic distance to quantify the relationships between genetic drift, selection, reproductive isolation. The activities from this work will help me to build a viable research program that will lead to an academic position, where I will be able to mentor other underrepresented minorities in biology.
