The PTC gene is among approximately 24 involved in tasting bitter substances, according to the U.

The university maintains a library of DNA samples from people throughout the world. U. and NIH experts searched the genetic variations concerning PTC tasting, examining the area of DNA that was pinpointed by Leppert's group. They used samples from 165 people — 31 Africans, 69 Asians, 55 Europeans or Utahns of European descent and 10 American Indians.

"Among Europeans we find that 60 to 70 percent of people can taste it and from 30 to 40 percent cannot," Wooding said.

"There's not much geographical difference," he added. However, "there seems to be an unusually high number of Native Americans who are able to taste the substance."

The researchers think one variant of the gene is targeted toward detecting a particular bitter taste (including PTC). The second type is similar, but not identical, probably identifying different bitter compounds.

When people inherit one gene of each type they may have a better ability to taste a wide variety of bitter flavors. If they inherit two of the type most likely to detect PTC, they are able to taste it strongly. If they inherit two genes of the second type, they are unable to taste PTC.

The gene may not be as important as it once was in terms of warning that we should not snack on certain wild plants. However, it remains important from a medical standpoint.

According to Wooding, "It might predict things like your tendency to smoke and aspects of your diet."

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