Genetics and ecological speciation

Species originate frequently by natural selection. A general mechanism by which this occurs is ecological speciation, defined as the evolution of reproductive isolation between populations as a result of ecologically-based divergent natural selection. The alternative mechanism is mutation-order speciation in which populations fix different mutations as they adapt to similar selection pressures. Although numerous cases now indicate the importance of ecological speciation in nature, very little is known about the genetics of the process. Here, we summarize the genetics of premating and postzygotic isolation and the role of standing genetic variation in ecological speciation. We discuss the role of selection from…