behaviors are related to, but different from nicotine dependence. It also demonstrates the value in pursuing multiple SNPs in a region where one SNP has been definitively associated with behavior and has concomitant evidence for molecular function. It is likely that other genes found to be associated with complex behaviors will harbor multiple functional variants, which may be involved in different aspects in the development of the disorder. For example, the most significantly associated SNP in this study (rs578776) represents a possible target for early intervention, while SNP rs16969968 may be a more effective target for later treatment. Taken as a whole, these results underscore the complexity of smoking behavior phenotypes, and suggest different genetic signals in this region may contribute to different stages of tobacco use and dependence.
