PHILADELPHIA -- Long the bane of picky eaters everywhere, broccoli's taste is not just a matter of having a cultured palate; some people can easily taste a bitter compound in the vegetable that others have difficulty detecting. Now a team of Penn researchers has helped uncover the evolutionary history of one of the genes responsible for this trait. Beyond showing the ancient origins of the gene, the researchers discovered something unexpected: something other than taste must have driven its evolution.
The team was led by Penn researchers Sarah Tishkoff, a Penn Integrates Knowledge professor with appointments in the genetics department in Penn's Perelman School of Medicine and the biology department in the School of Arts and Sciences, and Michael C. Campbell, a postdoctoral fellow in the genetics department at the medical school, and included undergraduate and postdoctoral researchers from both the genetics and biology departments. The team included their collaborator Paul Breslin from the Monell Chemical Senses Center in Philadelphia and Rutgers University and researchers from the Muse de L'Homme in France, the National Institutes of Health and several African universities and research institutes.
Their research was published in the journal Molecular Biology and Evolution.
The researchers were interested in the gene TAS2R38, which codes for a bitter taste receptor protein with the same name. People with a certain version of that gene can taste a compound, phenylthiocarbamide, or PTC, which is chemically similar to naturally occurring bitter compounds, called glucosinolates, present in many foods, including cruciferous vegetables like broccoli and Brussels sprouts. These "tasters" find such foods to have a bitter taste that people with a different version can't detect. As a result, "nontasters" have been shown to consume fewer cruciferous vegetables.
Modern humans originated in Africa, and populations from that regio
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University of Pennsylvania