Figure 2

Hierarchical clustering analysis of COMT methylation in the UNC dataset. The clustergram is highlighted on the left to display the major clada or related groups of methylated CpGs for each dataset. Percent methylation is represented on a color continuum of bright yellow (0%), black (50%) to bright purple (100%). Colored bars on the right of the clustergram display the amplicon members of each group. (COMT_001 = dark blue, COMT_002 = salmon, COMT_003 = purple, COMT_005 = yellow, COMT_006 = purple, COMT_008 = green, COMT_010 = light blue, COMT_013 = red). Unsupervised hierarchical clustering analysis (HCA) by CpG unit of A 48 subjects and 110 CpGs shows 3 groups of subjects by COMT Val ¹⁵⁸ Met genotype, age, sex, and alcohol use (AUDIT score). Group A is enriched for VV + MV genotypes, Group B for MM + MV genotypes and high AUDIT scores, and Group C for VV + MM genotypes. B Clustergram reveals the 39 most differentially methylated CpGs after applying a 40% standard deviation filter, after which Group C becomes predominantly VV genotype enriched.