Approaches for identifying targets of positive selection

Despite significant advancements in both empirical and theoretical population genetics throughout the past century, fundamental questions about the evolutionary forces that shape genomic diversity remain unresolved. Perhaps foremost among these are the strength and frequency of adaptive evolution. To quantify these parameters, statistical tools are needed that are capable of effectively identifying targets of positive selection throughout the genome in an unbiased manner, and functional approaches are needed that are capable of connecting these identified genotypes with the resulting adaptively significant phenotypes. Here we review recent advancements in both statistical and empirical methodology, and discuss important challenges and opportunities that remain as researchers continue to uncouple the relative importance of stochastic and deterministic factors in the evolution of natural populations.