The ability to taste PTC (phenylthiocarbamide) and other bitter compounds probably evolved as a way to protect animals from eating poisonous plants, according to Wooding and Bamshad, senior authors of a study reported in the April 13 cover story in Nature. Being a PTC taster or non-taster has far-reaching implications for human behavior, such as in the foods people eat and even whether they smoke cigarettes, said Wooding, research assistant professor of human genetics at the U of U's Eccles Institute of Human Genetics.
Evidence that humans and chimpanzees harbor different kinds of mutations suggests that the similar patterns of PTC sensitivity in the two species may be an evolutionary coincidence. "With this particular gene, it shows that humans and chimps probably faced different pressures from natural selection," Wooding said. "Chimps and humans outwardly show the same patterns of variation, but the mutations in each species are affecting taste sensitivity in completely different ways."
About 75 percent of people worldwide can taste PTC, while the remaining quarter can't. PTC tasters are less likely to smoke cigarettes than non-tasters, but they're also less likely to eat cruciferous vegetables, such as broccoli, that are important sources of nutrition, Wooding said.
Differences in PTC sensitivity were first discovered in 1930, when American chemist Arthur Fox accidentally let loose some of the compound in his laboratory. Fox noted that while some people complained of a bad taste from PTC, others could not taste it al
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Contact: Phil Sahm
Phil.Sahm@hsc.utah.edu
801-581-2517
University of Utah Health Sciences Center
12-Apr-2006