smoking-related phenotypes in both the total and the male sample. Finally, considering the fact that the protein products of these nAChR subunit genes must assemble in order to form functional nAChRs, we also performed gene-gene interaction analysis on all SNPs in this genomic region and found the best interactive model involved five SNPs located in LOC123688, CHRNA3, and the intergenic region at the 5′ end of CHRNB4 that influences SI in the male sample.
