DNA methylation at CpG3 within the human PPARα gene promoter (A), CpG2 within PPARδ gene promoter (B), CpG2 within TGFβ1 exon 1 (C) and CpG3 within PDGFα gene promoter (D) in a number of samples (ranging from 3 to 9) resected from normal human liver from same donor was determined by pyrosequencing. Each patient is shown on x axis starting from youngest (furthest to the left) then ranked by age up to the oldest on the right of the x axis. Female patients are shown in red and males in blue dots. Each dot represents the level of DNA methylation in one sample of donor liver. Results are expressed as percentage of DNA methylation.