Researchers report in the Feb. 21 issue of Science that they have identified the gene that determines the ability to distinguish a wide class of bitter tastes, a finding that may shed new light on dietary choice, nutritional status and tobacco use.
The identified gene, called PTC after the compound phenylthiocarbamide that is used to study the ability to taste bitter substances, exists in five forms throughout the world and codes part of the bitter taste receptor complex existing in the cells of tongue, explained project leader Dennis Drayna, Ph.D., National Institute on Deafness and Other Communication Disorders, National Institutes of Health.
One of the forms of the gene is responsible for a severe deficit in taste ability and has been traced to millions of people throughout the world who share a common prehistorical ancestor. Studies over the past 70 years have shown that about 30 percent of the U.S. population are "PTC nontasters," meaning they experience this tasting deficit, while 70 percent experience the taste of PTC as varying degrees of bitterness.
This genetic predisposition could help explain a wide range of dietary choices and responses to tobacco use, investigators said. For example, PTC nontasters may not experience the bitter taste of nicotine in cigarettes and may be at greater risk for prolonged smoking.
"This research promises to open a pathway to better understanding about what drives certain human behaviors, including those associated with smoking and eating," said James F. Battey, Jr., M.D., NIDCD director. "This is how basic science launches new ways to think about human behavior and its foundations."
Other institutions collaborating on this research include the Stanford University Genetics Department, the University of Utah departments of human genetics and psychiatry and the University of Utah Medical Center.
