An identical variability in taste sensitivity evolved independently in chimpanzees and humans according to research in the April 13, 2006 issue of Nature (Vol. 440, No. 7086, pp. 930-934). The two species share variability in their taste sensitivity to a bitter compound known as phenylthiocarbamide (PTC). This research contradicts a previous report in Nature 65 years ago, which suggested natural selection was responsible for 'taster' and non-'taster' individuals in each species.
Sensitivity to bitter taste is crucial for identifying the presence of toxic compounds, allowing animals to exploit and monitor their consumption of toxic foods. In humans and chimpanzees, individuals either recognize PTC as a bitter taste, or cannot taste it at all. Armed with the knowledge of the gene responsible for PTC sensitivity, Wooding and colleagues now revisit the original comparative experiment. They find that the mutation responsible for the polymorphism of the gene in chimpanzees is different to that in humans, demonstrating that the genetic code for non-'taster' individuals has evolved at least twice in hominids.
The authors suggest the characterization of such patterns could have important implications for nutrition and health.
Stephen Wooding (University of Utah, Salt Lake City, UT, USA)
(C) Nature press release.
Message posted by: Trevor M. D'Souza