Is FST obsolete?

Since the introduction of allozyme methods inthe mid 1960s it has been a standard practiceto report Wright's measure of populationsubdivision, FST, for surveys ofgenetic variation. Its widespread use hasprovided us with a sense of what values can beexpected in particular situations and how theycan be interpreted. With some theoreticaljustification, FST has also beenused to estimate rates of gene flow. Howeverthere are conditions under which FSTis inappropriate for gene flow estimation andcan lead to incorrect or even absurdconclusions. These pitfalls have promptedcritics to suggest that FST hasfailed to deliver what its proponents havepromised and should be abandoned. A furtherchallenge has been the development of newmethods that offer even greater promise. Thusit is reasonable to ask if perhaps it is timeto retire FST and turn to new andmore powerful methods for the inference of geneflow from genetic markers. Here I will arguethat although gene flow should be estimated bymore powerful approaches whenever practical,FST remains a useful measure of theaverage effects of gene flow and will continueto be used for comparative purposes.