Smoking status and the human dopamine transporter variable number of tandem repeats (VNTR) polymorphism: failure to replicate and finding that never-smokers may be different

Cigarette smoking, like many addictive behaviors, has been shown to have a genetic component. The dopamine transporter (DAT) gene (SLC6A3) encodes a protein that regulates synaptic levels of dopamine in the brain and is a candidate gene for addictive behaviors. We have collected smoking information from a national probability sample of 3383 adult volunteers contacted via a random-digit dialing telephone interview. A subset of individuals provided DNA from cheek swabs returned via the mail for subsequent genetic analysis of self-reported smoking behavior. DNA samples were genotyped at a variable number of tandem repeats (VNTR) polymorphism in the 3'-untranslated region of the DAT gene. If we classify smokers as non- (