11 chromosomes that have been identified in nicotine dependence linkage analyses, regions on chromosomes 9, 10, 11, and 17 have been detected by the greatest number of studies; chromosomes 1, 5, 10, 11, 12, 16, 20, and 22 have also shown some linkage signals (Li 2008). Overall, linkage analysis has identified several different loci that are linked to nicotine addiction and has been a starting point for identification of genes that may influence nicotine dependence phenotypes (Han et al. 2010). The results of linkage analyses have, in some cases, led to candidate gene association studies of nicotine dependence phenotypes.
