Similarly, population stratification and other unmeasured third variables, both environmental and genetic in nature, may account for these results (Hutchison et al., 2004). This may be especially relevant to GABRG1 genes as Enoch and colleagues (2009) have examined 2 independent populations and found evidence of selection pressure for various alcohol use disorder-linked SNPs. These results may also shed light on the departures from HWE observed for both SNPs in this study. Admixture and selection bias are among the strongest possible explanations for deviations from HWE. To exclude population stratification as an explanation for the associations observed in this study, we reanalyzed the data for individuals of European Ancestry only and doing so did not significantly alter any of the results reported herein. Thus stratification does not appear to account for the results obtained in this study.
