A measure of population subdivision based on microsatellite allele frequencies.

TLDR

R(ST) is a microsatellite‑based measure analogous to Wright’s F(ST) that quantifies the proportion of genetic variation between populations. The authors propose a new measure of population subdivision, R(ST), inferred from microsatellite allele frequencies and evaluate it via computer simulations. The measure incorporates a generalized stepwise mutation model for microsatellites and its performance was assessed by simulating subdivided populations and comparing R(ST) to F(ST). Under the generalized stepwise mutation model, R(ST) yields relatively unbiased estimates of migration rates and divergence times, whereas F(ST) underestimates population differentiation, especially at low migration or long divergence.

Abstract

A new measure of the extent of population subdivision as inferred from allele frequencies at microsatellite loci is proposed and tested with computer simulations. This measure, called R(ST), is analogous to Wright's F(ST) in representing the proportion of variation between populations. It differs in taking explicit account of the mutation process at microsatellite loci, for which a generalized stepwise mutation model appears appropriate. Simulations of subdivided populations were carried out to test the performance of R(ST) and F(ST). It was found that, under the generalized stepwise mutation model, R(ST) provides relatively unbiased estimates of migration rates and times of population divergence while F(ST) tends to show too much population similarity, particularly when migration rates are low or divergence times are long [corrected].