Using SAS 9.2 (www.sas.com), the χ2 goodness-of-fit test tested for deviations from HWE for each SNP, and correlation and Lewontin's D′ (Lewontin, 1964) was calculated to measure linkage disequilibrium (LD) between the SNPs, in the entire set of genotyped samples, i.e, not limited to lifetime drinkers, since these are population based estimates (Tables 1, 2).
