According to HapMap, rs2036527:G>A is in almost perfect LD (D′=0.979, r2=0.902) with rs16969968:G>A in Europeans, but these SNPs are in moderate to low LD, respectively, in Asians (D′=0.872, r2=0.673) and African-Americans (D′=0.87, r2=0.218). The LD between rs2036527:G>A and rs16969968:G>A was slightly higher in our African-American heavy smoker population (Fig. 2, D′=0.965, r2=0.302) than found in HapMap and the MAF of rs16969968:G>A was higher in our African-American heavy smoker population (9.6%) than in either the 1000 genomes ASW (7%) or NHLBI_ESP African-American (6%) populations. This suggests that, similar to European and Asian populations (Berrettini et al., 2008; Chen et al., 2012), at least one hypo-functional α5 allele (Bierut et al, 2008; Kuryatov et al., 2011; Tammimäki et al, 2012) might be contributing to heavy smoking in a subset of our re-sequenced African-American population.
