DNA methylation patterns in alcoholics and family controls

Table 2 Global methylation scores

	Alcohol-dependent siblings	Non-alcoholic siblings
Global methylation index for 1287 CpG sites
Mean methylation (SD)	0.282 (0.016)	0.282 (0.012)
Median methylation (SD)	0.082 (0.010)	0.079 (0.009)
Range	0.01-0.97	0.01-0.97
Sib pair difference in global methylation level at each of 1287 sites (alcoholic minus non-alcoholic sibling methylation level)
Mean difference (SD)	0.00005 (0.019)
Replicate pair difference in methylation level at each of 1287 sites (3 non-alcoholic and alcoholic siblings with replicate bisulfite treatment and methylation quantification)
Mean difference (SD)	0.0008 (0.006)	0.001 (0.003)

No global measures of methylation significantly differ between groups.