DNA Methylation

DNA methylation, one of the most studied epigenetic modifications, refers to the addition of a methyl group to the fifth carbon of cytosine (C) catalyzed by DNA methyltransferases(Dnmts), forming 5-methylcytosine (5mC). DNA methylation predominantly occurs inCpGs but is also found in non-CpG contexts. DNA methylation is heritable and has been associated with multiple cellular processes, including transcriptional repression transposon inactivation,  chromosome inactivation, embryonic development, genomic imprinting, and the alteration of chromatin structure.