By attaching a chemical tag to a DNA strand, this epigenetic process safely represses transcription. It effectively silences the sequence without altering the core genetic code.

While twins share identical genomes, differing lifestyles and environments alter their epigenetic tags over time, causing their once-similar genetic expressions to drift apart.

Researchers use epigenetic clocks to track predictable methylation changes. This reveals true cellular wear and tear much more accurately than a chronological birth year.

The attached methyl groups physically protrude from the DNA helix. This creates a molecular roadblock that stops transcription factors from binding to the promoter region.