Loss of Olfactory Receptor Genes Coincides with the Acquisition of Full Trichromatic Vision in Primates
Academic Editor: David Hillis, University of Texas at Austin
PLoS Biol 2(1): e5. This is an open-access article distributed under
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receptor (OR) genes constitute the molecular basis for the sense of
smell and are encoded by the largest gene family in mammalian genomes.
Previous studies suggested that the proportion of pseudogenes in the OR
gene family is significantly larger in humans than in other apes and
significantly larger in apes than in the mouse. To investigate the
process of degeneration of the olfactory repertoire in primates, we
estimated the proportion of OR pseudogenes in 19 primate species by
surveying randomly chosen subsets of 100 OR genes from each species. We
find that apes, Old World monkeys and one New World monkey, the howler
monkey, have a significantly higher proportion of OR pseudogenes than
do other New World monkeys or the lemur (a prosimian). Strikingly, the
howler monkey is also the only New World monkey to possess full
trichromatic vision, along with Old World monkeys and apes. Our
findings suggest that the deterioration of the olfactory repertoire
occurred concomitant with the acquisition of full trichromatic color
vision in primates.