Methylation of Cytosine Bases

Definition

This refers to a biochemical process where a methyl group is added to cytosine bases in DNA. This usually results in reduced gene activity because it prevents transcription factors from accessing the DNA.

Related terms

DNA Methyltransferase: The enzyme responsible for adding a methyl group to DNA.

CpG Island: A region with a high frequency of cytosine and guanine base pairs, often found near gene promoters and frequently targeted for methylation.

Demethylation: The removal of a methyl group from DNA, which can increase gene activity.