polygenic adaptation

Pritchard JK, Pickrell JK & Coop G 2010 The genetics of human adaptation: hard sweeps, soft sweeps, and polygenic adaptation. Curr Biol 20:R208-R215.

• most of the recent literature in human population genetics focuses on models of selection at one, or a small number of loci
• this is in contrast to classical models of natural and artificial selection in quantitative genetics
• where it is assumed that most traits of interest are highly polygenic, and are influenced to a small degree by standing variation at many loci

• short-term adaptation takes place by selection on standing variation at many loci simultaneously
• it may be very common for selection to push alleles upwards in frequency, but generally not to fixation
• this type of process could allow very rapid adaptation, yet be difficult to detect using most current population genetic methods
• the example of human height illustrates these issues