There are additional markers of interest in this region that are not strongly correlated with bin A. Because of the clear association between smoking behavior and bin A, each of the large-scale meta-analyses of European ancestry samples carried out association tests conditional on bin A variants for other SNPs to determine whether additional genetic markers in 15q25 are associated after adjusting for effects of bin A [Liu, et al. 2010; Saccone, et al. 2010; TAG 2010; Thorgeirsson, et al. 2010]. After conditioning on bin A, the meta-analyses identified additional SNPs in this region associated with smoking behavior. These SNPs can be grouped into three distinct bins (B, C, D) (Table 1). Bin B, tagged by rs588765 and rs880395, is associated with genome-wide significance among heavy versus light smokers but only in analyses conditioning on bin A (p=1.2×10−9) [Saccone, et al. 2010]. Notably, bin B is also associated with mRNA levels of CHRNA5 in brain and lung [Falvella, et al. 2010; Smith, et al. 2010; Wang, et al. 2009]. Bin C, tagged by rs6495308 [Liu, et al. 2010], rs2036534 [Thorgeirsson, et
