DNA demethylation can occur by an active process at the site of a 5mC in a DNA sequence or, in replicating cells, by preventing addition of methyl groups to DNA so that the replicated DNA will largely have cytosine in the DNA sequence (5mC will be diluted out).

Can we Demethylate DNA?

DNA demethylation is the process of removal of a methyl group from cytosines. DNA demethylation can be passive or active. The passive process takes place in the absence of methylation of newly synthesized DNA strands by DNMT1 during several replication rounds – for example, upon 5-azacytidine treatment [23].

How do you methylate DNA?

Usually, the two approaches of DNA methylation are either methylated-sensitive restriction enzymes or treatment with sodium bisulphite. Methylated sensitive restriction enzymes work by cleaving specific CpG, cytosine and guanine separated by only one phosphate group, recognition sites when the CpG is methylated.