Definition
DNA methylation is the addition of a methyl group to specific DNA sites, most commonly at cytosine–guanine (CpG) dinucleotides. It generally acts to silence gene expression, though not always simply.
Why it matters
Methylation is the most commonly cited epigenetic mechanism in popular writing. Understanding it accurately — including its limits — protects against overreach.
The Science
DNA methylation patterns change across development, tissues, and time. Some methylation changes are stable; others are dynamic. Environmental factors influence methylation in documented ways, though the magnitude and clinical significance vary greatly.
The NSI Perspective
NSI treats methylation as one signaling system among many — real, but not the master switch popular writing sometimes implies.
Clinical Implications
Consumer methylation tests marketed for a wide range of claims often exceed the underlying evidence.
Practical Application
If someone tells you your problems are all methylation, ask which methylation, at which sites, with what effect. Precision protects.
References
- 1.Jones PA. Functions of DNA methylation: islands, start sites, gene bodies and beyond. Nat Rev Genet. 2012;13(7):484–492.