Similarly, estimates based on pairwise relationships between individuals, derived from all of the GABA system markers in the autosome and on the X chromosome, did not explain any of the variance in alcohol use or symptomatology. The proportion of variance in the two alcohol use variables explained by all available autosomal SNPs (but not all available chromosome X SNPs) is appreciable, approximating or exceeding 10%, although less than most similar pedigree-based estimates (Grant et al., 2009; Slutske et al., 1999), and statistically significant only for the drinking index. This is likely because pairwise genetic correlations computed using this method only reflect the common variants that are tagged by the available genotyped SNPs (Yang et al., 2011).
