In: Biology
Epigenetics is the study of changes in gene expression that are not attributed to the changes in the primary DNA structure i.e, the underlying nucleotide sequence is not changed. So, there is a change in the phenotype without a change in the genotype of the individual i.e, the transmission occurs epigenetically.
Transmission of such epigenetic modifications across generations is called epigenetic inheritance.
Examples of epigenetic modifications : DNA methylation, Histone modification.
DNA methylation is a process by which methyl groups are added to the DNA molecule, which prevents certain genes from being expressed. DNA methylation regulates gene expression by inhibiting the binding of transcription factor to DNA, thus preventing transcription.
Histone modification - The DNA of each cell is wrapped around histone octamers. A post-translational modification to histone proteins is called Histone modification. Histone modification includes histone methylation, demethylation, phosphorylation, acetylation etc. These modifications can alter the chromatin structure and thus regulate gene expression.