No SNP deviated significantly from Hardy-Weinberg equilibrium (all p > .05). Pairwise evaluation of linkage disequilibrium detected a haploblock within each gene. In DRD1 (Figure 1A), D′ between rs4532 and rs265978 was 1.0, with haplotype frequencies of 67.6% for T-T, 23.8% for C-C, and 8.6% for T-C. In DRD2 (Figure 1B), rs2283265, rs1076560 and rs1800497 (D′=1.0) comprised the haploblock, with haplotype frequencies of 71.7% for C-C-G, 13.8% for C-C-A, 13.2% for A-A-A, and 1.4% for C-A-A.
