Table 7.
Characteristics of ageing-associated methylation sites
| Hypermethylated | Hypomethylated | |
|---|---|---|
| n | 3925 | 4615 |
| CpG island location | CpG islands | Non-CGI |
| Genomic location | TSS, 1st exon | Gene body, outside genes |
| Associated genes | 1832 | 2057 |
| GO function terms | 36 | 27 |
| GO process terms | 265 | 53 |
| Canonical pathways (IPA) | 19 | 3 |
| Transcription factors | 24 | 1 |
The CpG island location and genomic location refer to the sites where hyper- and hypomethylated sites are most abundant. Notably, there are more hypomethylated CpG sites compared with hypermethylated CpG sites and therefore also more hypomethylation-associated genes, yet the hypermethylation-associated genes are enriched in more GO terms and canonical pathways, and they share more common transcription factors.