Epigenetics

Article By:

Cunliffe, Vincent T. MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom.

Last reviewed:February 2022

DOI:https://doi.org/10.1036/1097-8542.238210

Show previous versions

• Epigenetic mechanisms in development, published June 2011:Download PDF Get Adobe Acrobat Reader

The study of heritable (stable) changes in gene expression and function that are not attributed to alterations of the DNA sequence. The epigenome represents the complete set of epigenetic modifications possessed by an organism or an individual cell. Epigenetic mechanisms give rise to heritable phenotypes through alterations to chromosomes that do not involve changes in their DNA sequence. Thus, epigenetic mechanisms are systems that facilitate the structural adaptation of chromosomal regions in order to record or propagate a change in the transcriptional activity of the genes contained within those regions. Transcriptional programming of multicellular development involves regulated interactions between DNA-binding transcription factors and specific DNA sequences in the regulatory regions of target genes. Through these sequence-specific DNA recognition events, transcription factors either activate or repress target gene transcription. In eukaryotic cells, genes are assembled into supercoiled complexes of DNA, histones (Fig. 1), and other proteins, known as chromatin. Epigenetic mechanisms help to realize and reinforce the transcriptional decisions made when transcription factors are recruited to specific genes, by introducing, removing, or perpetuating covalent modifications of chromatin structure. These covalent modifications are thought to create a molecular memory of decisions taken to activate or repress gene transcription and they may be inherited in specific cell lineages through successive cell divisions. See also: Chromosome; Deoxyribonucleic acid (DNA); Epigenome; Gene; Histone; Transcription

The content above is only an excerpt.