QST–FST comparisons: evolutionary and ecological insights from genomic heterogeneity

Key Points Comparison of divergence in quantitative traits ( Q ST ) with divergence in neutral molecular markers ( F ST ) allows the identification of trait divergence caused by natural selection, as opposed to genetic drift. Substantial conceptual, theoretical and methodological improvements to the Q ST – F ST approach have been achieved in recent years, and the number of studies using the Q ST – F ST approach has increased exponentially. Q ST – F ST comparisons have uncovered widespread genomic heterogeneity and adaptive differentiation in a wide range of taxa and traits. The Q ST – F ST method is still underused in 'omics' contexts, in which it may be useful for identifying evolutionary significance in large data sets in the absence of evolutionary models. Comparisons of quantitative trait ( Q ST ) and neutral molecular marker ( F ST ) divergence allow genetic drift and natural selection to be distinguished between as causes of population differentiation. Q ST – F ST comparisons are being increasingly used to tackle a range of evolutionary and ecological questions. Comparative studies of the divergence of quantitative traits and neutral molecular markers, known as Q ST – F ST comparisons, provide a means for researchers to distinguish between natural selection and genetic drift as causes of population differentiation in complex polygenic traits. The use of Q ST – F ST comparisons has increased rapidly in the last few years, highlighting the utility of this approach for addressing a wide range of questions that are relevant to evolutionary and ecological genetics. These studies have also provided lessons for the design of future Q ST – F ST comparisons. Methods based on the Q ST – F ST approach could also be used to analyse various types of 'omics' data in new and revealing ways.