<p>The aim of the study was to discover new epigenetic biomarkers of aging. We used a genome-wide screen for genetic loci showing consistent changes of DNA methylation with progressive aging. </p><p>Blood DNA samples from 19 apparently healthy individuals aged 22-80 years obtained from the NINDS repositories were analyzed for DNA methylation using Reduced Representation Bisulfite Sequencing. We followed the New England Biolabs (NEB) protocol for methylated adaptors as described previously. Briefly, 1 microgram of genomic DNA was spiked with 100 picograms of lambda phage DNA as the unmethylated standard and digested with MspI endonuclease at C’CGG sites. Ends of restriction fragments were filled in, 3’-dA tailed and methylated adaptors were ligated to the ends of restriction fragments. Bisulfite treatment using the Epitect kit (Qiagen) followed. Bisulfite-converted libraries were amplified using EpiMark Taq DNA polymerase (NEB) and primers with dual barcode indices. The libraries were pooled and sequenced on Illumina HiSeqX instrument using paired end reads of 150 bases. We used Bismark v0.23.1 to align the sequences to hg19 human genome assembly. We used methylKit v1.22.0 to analyze differential methylation in individuals of different ages. </p>

Epigenetic Biomarkers of Aging