Exegeses on maximum genetic differentiation.

A canon of population genetics concerns the properties of FST, a descriptor of spatial genetic structure. Interest for FST arose from Wright's early insights linking FST to dispersal parameters as well as to his concept of effective population size (e.g., Wright 1938, 1951). Although there is continued interest in this topic, FST also serves in other applications, such as detecting selected markers in natural populations (Beaumont and Nichols 1996) and more often in routine descriptive works. Remarkably, it is the latter use that seems to attract most discussion. Alternative descriptors have been proposed. Conversely, attempts have been made to draw biological inferences from FST properties that do not depend on biological processes. A reconsideration of its properties under biological scenarios underlines the weaknesses of such approaches.