Epigenetics

Epigenetics means above genetics. It determines how much and whether a gene is expressed without changing DNA sequences. Epigenetic regulations include, 1. DNA methylation: the addition of methyl group to DNA, converting cytosine to 5-methylcytosine, mostly at CpG sites; 2. Histone modifications: posttranslational modificationEpigeneticss of histone proteins including acetylation, methylation, ubiquitylation, phosphorylation and sumoylation; 3. miRNAs: non-coding microRNA downregulating gene expression; 4. Prions: infectious proteins viewed as epigenetic agents capable of inducing a phenotype without changing the genome.