Independent evolution of bitter-taste sensitivity in humans and chimpanzees.

Bibliographic Collection: 
MOCA Reference, APE
Publication Type: Journal Article
Authors: Wooding, Stephen; Bufe, Bernd; Grassi, Christina; Howard, Michael T; Stone, Anne C; Vazquez, Maribel; Dunn, Diane M; Meyerhof, Wolfgang; Weiss, Robert B; Bamshad, Michael J
Year of Publication: 2006
Journal: Nature
Volume: 440
Issue: 7086
Pagination: 930-4
Date Published: 2006 Apr 13
Publication Language: eng
ISSN: 1476-4687
Keywords: Alleles, Animals, Base Sequence, Biological Evolution, Genotype, Gorilla gorilla, Humans, Pan troglodytes, Phenotype, Phenylthiourea, Receptors, Cell Surface, Receptors, G-Protein-Coupled, Taste

It was reported over 65 years ago that chimpanzees, like humans, vary in taste sensitivity to the bitter compound phenylthiocarbamide (PTC). This was suggested to be the result of a shared balanced polymorphism, defining the first, and now classic, example of the effects of balancing selection in great apes. In humans, variable PTC sensitivity is largely controlled by the segregation of two common alleles at the TAS2R38 locus, which encode receptor variants with different ligand affinities. Here we show that PTC taste sensitivity in chimpanzees is also controlled by two common alleles of TAS2R38; however, neither of these alleles is shared with humans. Instead, a mutation of the initiation codon results in the use of an alternative downstream start codon and production of a truncated receptor variant that fails to respond to PTC in vitro. Association testing of PTC sensitivity in a cohort of captive chimpanzees confirmed that chimpanzee TAS2R38 genotype accurately predicts taster status in vivo. Therefore, although Fisher et al.'s observations were accurate, their explanation was wrong. Humans and chimpanzees share variable taste sensitivity to bitter compounds mediated by PTC receptor variants, but the molecular basis of this variation has arisen twice, independently, in the two species.

DOI: 10.1038/nature04655
Alternate Journal: Nature