Homologous Aging-Associated CpG Analysis

Homology alignments of human and murine genomes for the 105 CpGs were performed with the Ensembl genome browser with 121 nucleotide windows. A MATLAB script was used to find CpGs in the Illumina HumanMethylation450 BeadChip (450k) that were located either inside these homolog regions (categorized as “homolog”) or we determined the distance in base pairs (bp) to the center of the closest homolog region (categorized as “distance”). To further investigate age-associated changes at these CpGs the GSE40279 dataset was employed (Hannum et al., 2013 (link)). Data was analyzed with the R package GEOquery. Beta-values were used to determine the Pearson correlation with chronological age for all CpGs. The p-value of the correlations (α < 0.01) was estimated with a t-test for linear correlation with Bonferroni-correction for the total amount of CpGs on the 450k array.