The methylome of the aging human epidermis. (A) Dinucleotide context of non-converted cytosine residues. (B) Methylation levels of individual CpG dinucleotides. Average methylation levels were determined for all covered CpG dinucleotides and then distributed into bins with increasing methylation ratios. Percentages indicate the fractions of unmethylated (light orange), partially methylated (orange) and completely methylated (dark orange) CpGs. (C) Average DNA methylation ratios of the genome (all), promoters, gene bodies and intergenic regions are shown for the young (blue) and old sample (red), respectively. (D) The methylation pattern of chromosome 8, shown in tracks of 100-kb windows. The blue line indicates the young sample, the red line indicates the old sample. (E) Density plot of average methylation ratios for 100-kb windows covering the entire genome. Numbers indicate the number of windows with a methylation difference >0.15 (dotted line). (F) Density plot of average DNA ratios for 5-CpG windows covering chromosome 4.