Biochemical Basis of Epigenetics
Biochemical Basis of Epigenetics
Epigenetics is the study of changes in gene expression or cellular phenotype that do not involve alterations in the DNA sequence. These changes can be heritable and can be influenced by environmental factors. The biochemical basis of epigenetics lies in the modifications of DNA and histone proteins, which can regulate gene expression.
DNA Methylation
One of the most well-studied epigenetic modifications is DNA methylation, which involves the addition of a methyl group to cytosine residues in the DNA sequence. This modification typically occurs at CpG dinucleotides and is associated with gene silencing. DNA methylation patterns can be altered by environmental factors and can be inherited through cell division.
Histone Modifications
Histone proteins play a crucial role in packaging DNA into chromatin and regulating gene expression. Post-translational modifications of histones, such as acetylation, methylation, phosphorylation, and ubiquitination, can alter the accessibility of DNA to transcription factors and RNA polymerase. These modifications can activate or repress gene expression and are reversible, allowing for dynamic regulation of gene activity.
Non-Coding RNAs
In addition to DNA methylation and histone modifications, non-coding RNAs also play a role in epigenetic regulation. MicroRNAs and long non-coding RNAs can interact with mRNA transcripts and regulate their stability and translation. These non-coding RNAs can influence gene expression patterns and contribute to the epigenetic landscape of the cell.
Epigenetic Inheritance
Epigenetic modifications can be inherited through cell division and, in some cases, across generations. This inheritance pattern can be influenced by environmental factors and can have long-lasting effects on gene expression and cellular phenotype. Understanding the biochemical basis of epigenetics is crucial for unraveling the complexity of gene regulation and its role in development, disease, and evolution.
