Which epigenetic mechanism refers to the addition of methyl groups to DNA?

The process of adding methyl groups to DNA is known as DNA methylation. This epigenetic mechanism involves attaching a methyl group (CH3) to the cytosine base of DNA, typically in the context of cytosine-guanine (CpG) dinucleotides. DNA methylation plays a crucial role in regulating gene expression; high levels of methylation in the promoter region of a gene are often associated with reduced transcription and silencing of that gene.

This addition of methyl groups influences how tightly DNA is packaged around histones and can affect the accessibility of the DNA for transcription. Overall, DNA methylation is an essential mechanism for controlling gene activity without changing the underlying DNA sequence, contributing to cellular differentiation and the regulation of various biological processes.

In contrast, histone acetylation involves the addition of acetyl groups to histone proteins, which typically relaxes chromatin structure and promotes gene expression. Chromatin remodeling refers to the dynamic structural adaptations of chromatin, enabling access to DNA for various processes. Histone modification encompasses a broad range of chemical changes to histone proteins, including but not limited to acetylation and methylation, which also regulate gene expression.