Association of Childhood Chronic Physical Aggression with a DNA Methylation Signature in Adult Human T Cells
Figure 1
Gene promoters differentially methylated between CPA (n = 8) and controls (n = 12) in T cells.
A. Bar heights indicate the degree to which each chromosome contains an unexpectedly high number of differentially methylated promoters. This was calculated by Fisher's exact test followed by adjustment for multiple testing by converting p-values to false discovery rates. Bar heights are -log10 values of the false discovery rates, so bars higher than the dashed line have false discovery rates below 0.05. B. Heatmap depicts normalized intensities of microarray probes contained in promoters (at most one per promoter) that best differentiate between CPA and control groups. Rows correspond to promoters and columns to subjects. Red indicates higher methylation in a row and green indicates lower methylation. The 900 differentially methylated probes represent 448 gene promoters where 171 are more methylated in CPA and 277 less methylated. C. CpG density of the differentially methylated promoters. Gene promoters more methylated in CPA have higher CpG density than the average CpG content of all promoters analyzed (p<6.3E-27). In contrast, promoters less methylated in CPA have lower CpG density than the overall average (p<0.00014). Gene promoters more methylated in CPA have also higher CpG density than the promoters less methylated in CPA (p<1.3E-33; Wilcoxon rank-sum test). Normalized CpG density is the density of CpG sites divided by the expected density calculated by multiplying the density of C sites by the density of G sites.