methyl group
Meaning of methyl group: A methyl group is a one-carbon chemical unit that, added to or removed from DNA or proteins, can switch nearby gene activity on or off.
Definition of methyl group
A methyl group is a small chemical group made of one carbon atom bonded to three hydrogen atoms. It does not exist independently in the body but instead attaches to a larger molecule, altering that molecule's chemical properties and, in some cases, its function.
The addition of methyl groups to DNA, a process called methylation, is one of the main ways cells regulate which genes are active without changing the underlying genetic sequence itself. Methyl groups can also attach to proteins and other molecules, affecting their stability, activity, or interaction with other molecules.
Patterns of DNA methylation can change with age, environment, and disease, and abnormal methylation patterns are studied for their role in conditions including cancer, where genes that would normally restrain cell growth can become silenced by excess methylation.
Used in a sentence
The laboratory analysis examined methyl group patterns across the gene's regulatory region.
Good to know
A methyl group's effect depends entirely on where it attaches, since methylation of DNA can silence a gene while methylation elsewhere in a molecule can have a very different, or no, functional effect.
Word origin
Where “methyl group” comes from
Formed from Greek methy, meaning wine, and hyle, meaning wood or matter, the roots historically combined to name methanol, or wood spirit, from which the methyl group takes its name.