Adaptation and speciation: what can Fst tell us?

A useful way of summarizing genetic variability among different populations is through estimates of the inbreeding coefficient, Fst. Several recent studies have tried to use the distribution of estimates of Fst from individual genetic loci to detect the effects of natural selection. However, the promise of this approach has yet to be fully realized owing to the pervasive dogma that this distribution is highly dependent on demographic history. Here, I review recent theoretical results that indicate that the distribution of estimates of Fst is generally expected to be robust to the vagaries of demographic history. I suggest that analyses based on it provide a useful first step for identifying candidate genes that might be under selection, and explore the ways in which this information can be used in ecological and evolutionary studies.