BioFiles Volume 7, Number 3 — Epigenetics

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EpigeneticsTable of Contents

 


Introduction

Savita Bagga
Savita Bagga

Epigenetic modifications are stable, but potentially reversible alterations in the cell that affect gene expression independent of mutations in the DNA sequence. These modifications can be mitotically transmitted to daughter cells and, in some cases, to the next sexual generation.

The detailed molecular mechanisms underlying epigenetic modifications are still not known; a complex interplay of DNA methylation, chromatin remodeling, and specific forms of RNA-mediated degradation are involved. Epigenetic modifications are thought to occur through two key interconnected processes — DNA methylation and the covalent modification of histones.

Historically, it had been shown DNA is reversibly methylated. In addition, the associated DNA proteins, called histones, are altered by methylation, phosphorylation, acetylation, and other changes. These have been shown to associate with gene regulation. Epigenetic processes are natural and essential to many organism's functions, but if they occur improperly there can be major adverse health and behavioral effects resulting in diseases like cancers, autism etc.

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