Estimates of explained phenotypic variance (h2SNP) attributable to GABA system SNPs and all available SNPs, separately for autosomal and chromosome X markers, are shown in Table 5. Only the variance in the drinking index attributable to the full set of all available autosomal SNPs was significant, using a likelihood ratio test (LRT) of the null hypothesis that for each group of SNPs, h2SNP = 0. Neither autosomal nor chromosome X GABA system SNPs accounted for a significant proportion of the variance in either alcohol related phenotype.
