Multiple SNPs in 15q25 have been identified as associated with smoking behavior in studies of European ancestry subjects. We focused on the results highlighted in the most powerful studies, namely the large meta-analyses [Liu, et al. 2010; Saccone, et al. 2010; TAG 2010; Thorgeirsson, et al. 2010] (Table 1). Table 2 lists the 11 targeted SNPs and illustrates how linkage disequilibrium (LD, measured by r2) structure varies across different populations. We used SNAP [Johnson, et al. 2008] with 1000 Genomes Pilot 1 reference samples [Altshuler, et al. 2010; Durbin, et al. 2010] and HapMap3 ASW to obtain LD estimates for our three populations: CEU for European ancestry, JPT/CHB for Asians, and ASW/YRI for African Americans.
