Characteristics of age-associated CpG sites. (A) Methylation sites are shown based on their chromosomal location (x-axis). The percentage of sites was determined by the number of age-associated sites on each chromosome over the number of sites in the analysis on each chromosome (n = 137,168). (B) Histogram shows the distribution of genome-wide age-associated sites in relation to gene architecture. ‘Age-related’ sites are the 22,122 sites that were found to be genome-wide age-associated and ‘All’ are the locations of all the sites run in the analysis (n = 137,168). (C) Histogram of regression coefficients for 22,122 loci with genome-wide significant association with age.