A Scan for Positively Selected Genes in the Genomes of Humans and Chimpanzees

Research output: Contribution to journalJournal articlepeer-review

  • Nielsen, Rasmus
  • Carlos Bustamente
  • Andrew G. Clark
  • Stephen Glanowski
  • Timothy B. Sackton
  • Melissa J. Hubisz
  • Adi Fledel-Alon
  • David M. Tanenbaum
  • Daniel Civello
  • Thomas J. White
  • John J. Sninsky
  • Mark D. Adams
  • Michele Cargill
Since the divergence of humans and chimpanzees about 5 million years ago, these species have undergone a remarkable evolution with drastic divergence in anatomy and cognitive abilities. At the molecular level, despite the small overall magnitude of DNA sequence divergence, we might expect such evolutionary changes to leave a noticeable signature throughout the genome. We here compare 13,731 annotated genes from humans to their chimpanzee orthologs to identify genes that show evidence of positive selection. Many of the genes that present a signature of positive selection tend to be involved in sensory perception or immune defenses. However, the group of genes that show the strongest evidence for positive selection also includes a surprising number of genes involved in tumor suppression and apoptosis, and of genes involved in spermatogenesis. We hypothesize that positive selection in some of these genes may be driven by genomic conflict due to apoptosis during spermatogenesis. Genes with maximal expression in the brain show little or no evidence for positive selection, while genes with maximal expression in the testis tend to be enriched with positively selected genes. Genes on the X chromosome also tend to show an elevated tendency for positive selection. We also present polymorphism data from 20 Caucasian Americans and 19 African Americans for the 50 annotated genes showing the strongest evidence for positive selection. The polymorphism analysis further supports the presence of positive selection in these genes by showing an excess of high-frequency derived nonsynonymous mutations.
Original languageEnglish
JournalPLoS - Biology
Volume3
Issue number6
Pages (from-to)e170
ISSN1544-9173
DOIs
Publication statusPublished - 2005

ID: 87656