What are the major mechanisms of epigenetic genome modification?

Key Concepts

Epigenetics

Epigenetics refers to the study of heritable changes in gene expression that do not involve alterations to the underlying DNA sequence. These changes can affect how genes are turned on or off and can be influenced by environmental factors, lifestyle, and developmental stages. Understanding epigenetics is crucial for grasping how organisms adapt and respond to their surroundings.

DNA Methylation

DNA methylation is a key epigenetic mechanism involving the addition of a methyl group to the DNA molecule, typically at cytosine bases. This modification can repress gene expression by preventing the binding of transcription factors and other proteins necessary for gene activation. It plays a significant role in processes such as development, genomic imprinting, and X-chromosome inactivation.

Histone Modification

Histone modification involves the chemical alteration of histone proteins around which DNA is wrapped, influencing chromatin structure and gene accessibility. Common modifications include acetylation, methylation, and phosphorylation, which can either promote or inhibit gene expression. These modifications are dynamic and can be influenced by various factors, including environmental signals and cellular conditions.