Genetics and Genetic Disorders

Epigenetics & Chromatin

Epigenetics is the study of the configuration and chemistry of DNA in chromosomes and changes in gene expression patterns that cannot be traced to the DNA sequence. Unlike phenotypes that are associated with mutations in the underlying DNA code, epigenetic changes involve heritable covalent modifications to chromatin structure, such as DNA methylation and histone modification. Here we highlight common epigenetic markers, the techniques used to study them, and their role in biology and human disease. DNA is stored in a highly structured complex called chromatin. Epigenetic processes control gene expression by altering chromatin structure (Figure 1). Actively transcribed genes are associated with accessible chromatin regions, while transcriptionally silent genes are found in inaccessible chromatin regions. These modifications made to DNA and proteins, which impact chromatin structure, are referred to as epigenetic markers (or marks) and subsequently inherited as they are passed on through rounds of cell division.

• DNA Methylation. DNA methylation works by adding a chemical group to DNA
• Histone modification. DNA wraps around proteins called histones
• Non-coding RNA. Your DNA is used as instructions for making coding and non-coding RNA.