Fig. 1.
DNA methylation. DNMTs add a methyl group (CH3) to the carbon in the 5 position of cytosine, converting it to 5-methylcytosine. The donor of the methyl group is S-adenosylmethionine (SAM), which is converted to S-adenosylhomocysteine (SAH) (updated from Luczak and Jagodziński 2006; Osorio and Castillo 2016)