Download variations in perception of bitter go way back

Variations in Perception of Bitter Go Way Back
By Henry Fountain, The New York Times
August 14, 2009
They may not have a sweeter disposition, but some people can’t perceive bitter tastes
very well. Now a study from Spain shows that some Neanderthals were in the same
boat.
Bitter taste perception in humans has been studied most thoroughly with a chemical,
phenylthiocarbamide, or PTC, that is related to compounds in Brussels sprouts and
similar foods. About three-quarters of the world’s population perceives PTC as bitter,
while the other one-quarter doesn’t really taste it at all.
The difference lies in a gene, TAS2R38, that encodes proteins that are part of taste
receptors on the tongue. There are several variants of the gene, a dominant “taster” type
and a recessive “nontaster” type, which occur with about the same frequency. Only if a
person inherits a recessive type from both parents would she not be able to taste PTC.
Carles Lalueza-Fox of the Institute of Evolutionary Biology (CSIC-UPF) in Barcelona and
colleagues looked at the TAS2R38 gene in a virtually uncontaminated sample from a
48,000-year-old bone from an adult male Neanderthal collected at El Sidrón, a site in
northern Spain. They found similar variations in the gene, and determined that the
individual had one dominant form and one recessive form. That means the Neanderthal
could perceive bitter taste, though perhaps not as well as an individual with two
dominant forms of the gene.
The researchers say their findings, which were reported in Biology Letters, show that the
variation in perception of bitter taste started showing up before the human and
Neanderthal lineages began to diverge a half-million years ago or more.