A scan for human-specific relaxation of negative selection reveals unexpected polymorphism in proteasome genes

Mehmet Somel, Melissa A.Wilson Sayres, Gregory Jordan, Emilia Huerta-Sanchez, Matteo Fumagalli, Anna Ferrer-Admetlla, Rasmus Nielsen

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Environmental or genomic changes during evolution can relax negative selection pressure on specific loci, permitting high frequency polymorphisms at previously conserved sites. Here, we jointly analyze population genomic and comparative genomic data to search for functional processes showing relaxed negative selection specifically in the human lineage, whereas remaining evolutionarily conserved in other mammals. Consistent with previous studies, we find that olfactory receptor genes display such a signature of relaxation in humans. Intriguingly, proteasome genes also show a prominent signal of human-specific relaxation: multiple proteasome subunits, including four members of the catalytic core particle, contain high frequency nonsynonymous polymorphisms at sites conserved across mammals. Chimpanzee proteasome genes do not display a similar trend. Human proteasome genes also bear no evidence of recent positive or balancing selection. These results suggest human-specific relaxation of negative selection in proteasome subunits; the exact biological causes, however, remain unknown.

Original languageEnglish (US)
Pages (from-to)1808-1815
Number of pages8
JournalMolecular biology and evolution
Volume30
Issue number8
DOIs
StatePublished - Jan 1 2013

Keywords

  • Human evolution
  • Negative selection
  • Olfactory transduction
  • Proteasome
  • Relaxation of constraints

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics

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