Epigenetic mechanisms are processes that alter gene activity without changing the DNA sequence. The three primary mechanisms include DNA methylation, histone modification, and non-coding RNA interactions.
1. DNA Methylation: This involves the addition of a methyl group to the DNA molecule, usually at cytosine bases. Methylation typically acts to repress gene transcription.
2. Histone Modification: Histones are proteins around which DNA is wrapped. Modifications such as acetylation or phosphorylation of histones can either promote or repress gene transcription by altering chromatin structure.
3. Non-coding RNA: These RNA molecules do not code for proteins but can regulate gene expression at the transcriptional and post-transcriptional levels.
