DNA methylation
noun
: the enzymatically controlled addition of a methyl group to a nucleotide base (such as cytosine in eukaryotes) in a molecule of DNA that plays a role in regulating gene expression (as by the inhibition of genetic transcription)
When a methyl group attaches to a specific spot on a gene—a process called DNA methylation—it can change the gene's expression, turning it off or on, dampening it or making it louder.—John Cloud
A handful of drugs that affect DNA methylation already exist, and are being used to treat cancers in which faulty gene labeling plays a role.—Helen Pilcher
A process called DNA methylation sets down "marks" on bits of DNA and is typically thought to squelch gene expression.—Sarah Baldauf
DNA methylation is a mark on genomic DNA made by addition of methyl groups to cytosine bases …—Adrian Bird
Cite this Entry
“DNA methylation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/DNA%20methylation. Accessed 29 Jul. 2026.
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