In this study, by using the EM Haseman-Elston QTL regression method implemented in GENEHUNTER and the SIBPAL program of S.A.G.E., we obtained evidence for significant linkage of smoking rate to chromosome 11 and suggestive linkage to chromosomes 4, 7, 9, 14, and 17. Additionally, our results suggest that the genomic regions mapped on chromosomes 1, 6, 12, 15, 20, and 21 are of potential interest to harbor susceptibility genes for nicotine dependence at a significance level of 0.01. Of these loci, three loci on chromosomes 7, 11, and 17 were identified by both linkage analysis methods.
