Identification of non-taster Japanese macaques for a specific bitter taste.

Bitter taste perception evolved as a key detection mechanism against the ingestion of bioactive substances, and is mediated by TAS2R gene family members in vertebrates. The most widely known and best studied bitter substance is phenylthiocarbamide (PTC), which is recognized by TAS2R38 and has a molecular structure similar to that of glucosinolates contained in Brassica plants. The "non-taster" phenotypic polymorphism (i.e., not sensitive to PTC-containing foods) has been identified in many primates, including humans. Here, we report genetic and behavioral evidence for the existence of "non-taster" Japanese macaques, which originated from a restricted region of Japan. Comparison of the sequences of the TAS2R38 gene of 333 Japanese and 55 rhesus macaques suggested that this genotype appeared after the divergence of these two species, independently of the appearance of human and chimpanzee "non-tasters". This finding might give a clue for elucidating the ecological, evolutionary, and neurobiological aspects of bitter taste perception of primates, as related to the plants that they sometimes use as foods in their habitats.