Efforts to identify the genetic basis of human adaptations from polymorphism data have sought footprints of "classic selective sweeps" (in which a beneficial mutation arises and rapidly fixes in the population).Yet it remains unknown whether this form of natural selection was common in our evolution. We examined the evidence for classic sweeps in resequencing data from 179 human genomes. As expected under a recurrent-sweep model, we found that diversity levels decrease near exons and conserved noncoding regions. In contrast to expectation, however, the trough in diversity around human-specific amino acid substitutions is no more pronounced than around synonymous substitutions. Moreover, relative to the genome background, amino acid and putative regulatory sites are not significantly enriched in alleles that are highly differentiated between populations. These findings indicate that classic sweeps were not a dominant mode of human adaptation over the past ~250,000 years.

Original publication

DOI

10.1126/science.1198878

Type

Journal article

Journal

Science

Publication Date

18/02/2011

Volume

331

Pages

920 - 924

Keywords

Adaptation, Biological, Amino Acid Substitution, Biological Evolution, Chromosomes, Human, X, Conserved Sequence, Evolution, Molecular, Exons, Gene Frequency, Genetic Variation, Genome, Human, Haplotypes, Humans, Models, Genetic, Molecular Sequence Annotation, Mutation, Polymorphism, Single Nucleotide, Recombination, Genetic, Selection, Genetic, Untranslated Regions