The Genetics of Human Adaptation: Hard Sweeps, Soft Sweeps, and Polygenic Adaptation

By J. K. Pritchard, Joseph K. Pickrell, Graham Coop. Current Biology, 2010

928 citations recorded by the source corpus.

There has long been interest in understanding the genetic basis of human adaptation. To what extent are phenotypic differences among human populations driven by natural selection? With the recent arrival of large genome-wide data sets on human variation, there is now unprecedented opportunity for progress on this type of question. Several lines of evidence argue for an important role of positive selection in shaping human variation and differences among populations. These include studies of comparative morphology and physiology, as well as population genetic studies of candidate loci and genome-wide data. However, the data also suggest that it is unusual for strong selection to drive new mutations rapidly to fixation in particular populations (the ‘hard sweep’ model). We argue, instead, for alternatives to the hard sweep model: in particular, polygenic adaptation could allow rapid adaptation while not producing classical signatures of selective sweeps. We close by discussing some of the likely opportunities for progress in the field.

Subfields: Genetics

View Paper: https://www.semanticscholar.org/paper/a937f5ac7891d3e81870f7a87231edad5308e6f0

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In Genetics

Citations in the corpus

Progress and Promise of Genome-Wide Association Studies for Human Complex Trait Genetics (2011, background): “…positive selection described above, however, are based on detecting signals of selective sweeps at individual loci (Maynard Smith and Haigh 1974) and are not able to detect adaptive events that affected many alleles of small effect (Chevin et al. 2008; Hancock et al. 2010; Pritchard et al. 2010).”
The QTN Program and the Alleles That Matter for Evolution: All That’s Gold Does Not Glitter (2011, background): “…and of the subsequent extensive local adaptation of human populations bear few of the hallmarks of selective sweeps (Hernandez et al. 2011), and fixed differences among human populations are exceptionally rare, despite sufficient time for new mutations to have fixed (Pritchard et al. 2010).”
Robust Identification of Local Adaptation from Allele Frequencies (2012, background): “Many available tests for selection are designed to detect rapid complete sweeps from new mutations; however, such events are likely just a small percentage of adaptive genetic change (Coop et al., 2009; Pritchard et al., 2010; Cao et al., 2011; Hernandez et al., 2011).”
Heritability and the evolution of cognitive traits (2015, background): “Many cognitive traits are quantitative in nature, and thus should be expected to evolve as a result of selection on many small effect variants through polygenic adaptation (e.g., Pritchard and Di Rienzo 2010; Pritchard et al. 2010).”
Testing for Associations between Loci and Environmental Gradients Using Latent Factor Mixed Models (2012, background): “An alternative way to investigate signatures of local adaptation, especially when beneficial alleles have weak phenotypic effects, is by identifying polymorphisms that exhibit high correlation with environmental variables (Joost et al. 2007; Hancock et al. 2008; Coop et al. 2010; Poncet et al. 2010;”