Lineage-specific loss of function of bitter taste receptor genes in humans and nonhuman primates.

Bibliographic Collection: 
MOCA Reference, APE
Publication Type: Journal Article
Authors: Go, Yasuhiro; Satta, Yoko; Takenaka, Osamu; Takahata, Naoyuki
Year of Publication: 2005
Journal: Genetics
Volume: 170
Issue: 1
Pagination: 313-26
Date Published: 2005 May
Publication Language: eng
ISSN: 0016-6731
Keywords: Animals, Cell Lineage, Humans, Mice, Molecular Sequence Data, Primates, Protein Structure, Tertiary, Pseudogenes, Receptors, G-Protein-Coupled, Taste

Since the process of becoming dead genes or pseudogenes (pseudogenization) is irreversible and can occur rather rapidly under certain environmental circumstances, it is one plausible determinant for characterizing species specificity. To test this evolutionary hypothesis, we analyzed the tempo and mode of duplication and pseudogenization of bitter taste receptor (T2R) genes in humans as well as in 12 nonhuman primates. The results show that primates have accumulated more pseudogenes than mice after their separation from the common ancestor and that lineage-specific pseudogenization becomes more conspicuous in humans than in nonhuman primates. Although positive selection has operated on some amino acids in extracellular domains, functional constraints against T2R genes are more relaxed in primates than in mice and this trend has culminated in the rapid deterioration of the bitter-tasting capability in humans. Since T2R molecules play an important role in avoiding generally bitter toxic and harmful substances, substantial modification of the T2R gene repertoire is likely to reflect different responses to changes in the environment and to result from species-specific food preference during primate evolution.

DOI: 10.1534/genetics.104.037523
Alternate Journal: Genetics
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