Loss of olfactory receptor function in hominin evolution

PLoS One. 2014 Jan 2;9(1):e84714. doi: 10.1371/journal.pone.0084714. eCollection 2014.

Abstract

The mammalian sense of smell is governed by the largest gene family, which encodes the olfactory receptors (ORs). The gain and loss of OR genes is typically correlated with adaptations to various ecological niches. Modern humans have 853 OR genes but 55% of these have lost their function. Here we show evidence of additional OR loss of function in the Neanderthal and Denisovan hominin genomes using comparative genomic methodologies. Ten Neanderthal and 8 Denisovan ORs show evidence of loss of function that differ from the reference modern human OR genome. Some of these losses are also present in a subset of modern humans, while some are unique to each lineage. Morphological changes in the cranium of Neanderthals suggest different sensory arrangements to that of modern humans. We identify differences in functional olfactory receptor genes among modern humans, Neanderthals and Denisovans, suggesting varied loss of function across all three taxa and we highlight the utility of using genomic information to elucidate the sensory niches of extinct species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biological Evolution*
  • Databases, Nucleic Acid
  • Evolution, Molecular
  • Genome
  • Genomics
  • Hominidae / genetics*
  • Humans
  • Molecular Sequence Data
  • Multigene Family
  • Olfactory Receptor Neurons / metabolism*
  • Phylogeny
  • Receptors, Odorant / chemistry
  • Receptors, Odorant / classification
  • Receptors, Odorant / genetics*
  • Sequence Alignment

Substances

  • Receptors, Odorant

Grants and funding

This project was funded: by the Irish Research Council (IRC) Graduate Research Education Programme (GREP) awarded to GH, ECT and DH; a Science Foundation Ireland PIYRA 06/YI3/B932 awarded to ECT. (http://www.research.ie/) (http://www.sfi.ie). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript