Technical note: Measures of differentiation for quantitative traits

Studies of anthropological genetics and bioarcheology often examine the degree of among-group variation in quantitative traits such as craniometrics and anthropometrics. One comparative index of among-group differentiation is the minimum value of Wright's $$ as estimated from quantitative traits. This measure has been used in certain population-genetic applications such as comparison with $$ estimated from genetic data, although some inferences are limited by how well the data and study design fit the underlying population-genetic model. In many cases, all that is needed is a simple measure of among-group variation. One such measure is $$ , the proportion of total phenotypic variation accounted for by among-group phenotypic variation, a measure easily obtained from analysis of variance and regression methods. This paper shows that $$ and minimum $$ are closely related as $$ . $$ is computationally easy and may be useful in cases where all we need is a simple measure of relative among-group differentiation.