Interacting genes related to bitter taste sensitivity, TAS2R16 and TAS2R38, play an important role in a person's development of nicotine dependence and smoking behaviour, researchers at the University of Virginia Health System have found.
The researchers also found that people with higher taste sensitivity aren't as likely to become dependant on nicotine as people with decreased taste sensitivity.
Their findings one day may be key in identifying people at risk for nicotine dependence.
"This new knowledge is an important tool in predicting whether a person is likely to become a smoker or not," said lead investigator Ming Li, Ph.D., professor of psychiatry and behavioral neurosciences who specializes in addiction and genetics research.
It's long been known that a person's ability to taste bitter substances plays a crucial role in the rejection of potentially toxic foods, but taste sensitivity varies widely among individuals and between ethnic groups.
Previous studies have suggested a link between so-called taster status and nicotine dependence, but genetic evidence underlying such a link has been lacking.
The findings are based on a study of genetic data of more than 2,000 participants from more than 600 families of African American or European American origin.
"Until now, the method for analyzing gene to gene or gene to environment interactions could only handle one type of trait without correcting for other important covariants, such as age or gender, but we've developed a novel algorithm and corresponding computer program that can handle all types of genetic data and correct for any number of variants - gender, age, race, and so on," Li said.
"This new approach significantly expands our ability to study gene-gene or gene-environmental interactions. It provides a far better analytical tool for every scientist out there doing genetics work.
"We're laying an important foundation for addressing nicotine dependence. First we need to establish a comprehensive understanding of how all associated genes work together to affect smoking behaviours and addiction; that's what we're doing now. Once we have that base of knowledge, we can move on to develop effective prevention and treatment for nicotine dependence," Li added.
The study is published in the October 10, 2008 issue of The American Journal of Human Genetics.