What are the major mechanisms of epigenetic genome modification?

Verified step by step guidance

1. Understand that epigenetic modifications are changes to the genome that do not alter the DNA sequence but affect gene expression.
2. Recognize that DNA methylation is a key mechanism, where methyl groups are added to the DNA molecule, typically at cytosine bases, affecting gene expression.
3. Learn about histone modification, which involves the addition or removal of chemical groups to histone proteins, influencing how tightly DNA is wound around histones and thus gene accessibility.
4. Explore non-coding RNA molecules, such as microRNAs, which can regulate gene expression by interfering with the translation of mRNA into proteins.
5. Consider the role of chromatin remodeling, where the structure of chromatin is altered, affecting the accessibility of DNA to transcription machinery and thus gene expression.

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.