Sunday, April 16, 2006

Humans and chimps & bitter taste = convergent evolution   posted by Razib @ 4/16/2006 12:45:00 PM

From Nature, Independent evolution of bitter-taste sensitivity in humans and chimpanzees:

It was reported over 65 years ago that chimpanzees, like humans, vary in taste sensitivity to the bitter compound phenylthiocarbamide (PTC)1. This was suggested to be the result of a shared balanced polymorphism...In humans, variable PTC sensitivity is largely controlled by the segregation of two common alleles at the TAS2R38 locus...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...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 observations1 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.

Related: PTC taste, balancing selection?, PTC, part II, Taste & behavior genetics, Genetics of taste and Slow & diverse food.