Epigenetics is the study of heritable codes other than genetic codes written in A, G, C, and T. Epigenetic codes work as gene switches which regulate gene expressions; therefore, cells or individuals with the same genetic information can have different phenotypes. A tortoiseshell cat with brown and black spots is an example of cells with the same genetic information and different phenotypes. Monozygotic twins and cloned animals are examples of individuals with the same genetic information and different phenotypes.
DNA methylation and histone modifications (acetylation and methylation) serve as epigenetic code. DNA methylation shuts off genes and histone acetylation turns on genes.
|