Epigenome

Lore & Background

The epigenome is involved in regulating gene expression, development, tissue differentiation, and suppression of transposable elements. Unlike the underlying genome, which remains largely static within an individual, the epigenome can be dynamically altered by environmental conditions. The main types of epigenetic changes include DNA methylation, which involves the addition of a methyl group to the DNA molecule, typically at cytosine bases, generally leading to gene silencing.

Reader's Guide

The epigenome is significant because it explains how cells with identical genetic codes can perform different functions, and how environmental factors can influence gene expression without altering the DNA sequence itself. Its dynamic nature allows for adaptation, but also means that disruptions can contribute to disease. The study of the epigenome has revealed that inter-individual differences in DNA methylation are mainly determined by cis-regulatory sequence polymorphisms, and that most functionally relevant changes in CpG methylation occur in regulatory elements such as enhancers. Understanding the epigenome is crucial for comprehending development, disease mechanisms, and potential therapeutic interventions.

Did You Know?

• The human epigenome is dynamic and can be influenced by environmental factors such as diet, stress, and toxins.
• CoRSIVs (Correlated Regions of Systemic Interindividual Variation in DNA methylation) span only 0.1% of the human genome and are associated with genes involved in many human disorders.
• In human preimplantation embryos, there is a global DNA demethylation process after fertilisation, with the paternal genome demethylating quickly and the maternal genome being more resistant.
• DNA methylation imbalances between homologous chromosomes show sequence-dependent behavior, with CpG methylation imbalances exceeding 30% differences in 5% of loci.