Duffy explained that one measure for taste genetics is the bitterness of PROP. "Individuals who cannot taste the bitterness of PROP, or taste the bitterness of PROP as weak, are called nontasters. Those who taste the most bitterness are called supertasters. Previous research has found that PROP nontasters experience more positive, such as sweetness, and less negative, such as bitterness, irritation or astringency, sensations from alcoholic beverages and thus may be more likely to drink alcoholic beverages. Conversely, PROP supertasters have a sensory hindrance to consuming alcoholic beverages, because alcoholic beverages elicit more negative, such as bitterness or irritation, and less positive, such as sweetness, oral sensations."
Study participants (53 females, 31 males), primarily light and moderate drinkers, rated the bitterness of five PROP concentrations (0.032 - 3.2 mM). They were interviewed about how frequently during a year they consumed beer, wine, wine coolers, and liquor. Researchers also drew blood for genotyping from all participants in order to determine if the gene TAS2R38 which provides the blueprint for a protein that forms a receptor that allows individuals to taste bitter chemicals like PROP could predict PROP bitterness, alcohol sensations, and alcohol intake. Taste papillae on the anterior tongue (fungiform papillae) were also counted.
"There were two primary findings," said Duffy. "People who tasted the least bitterness from PROP or who were TAS2R38 nontasters consumed more alcohol than those who tasted the most bitterness from PROP or who were TAS2R38 tasters. For example, using PROP as a marker of taste genetics, those who tasted the least bitterness from PROP averaged consuming alcoholic beverages five to six times per week whereas those who tast