Patent ID: 7285394

Claim:
A method for labeling CpG sequences corresponding to methylated CpG sequences in an isolated genomic DNA sample, comprising: (a) obtaining a sample of isolated genomic DNA; (b) digesting the isolated genomic DNA with a restriction endonuclease to produce genomic DNA fragments; (c) treating the genomic DNA fragments with a 5-methylcytosine deglycosylase, whereby one or more 5-methylcytosine bases are removed to produce abasic genomic DNA fragments; and (d) treating the abasic genomic DNA fragments with base excision repair (BER) enzymes in the presence of labeled dCTP, whereby 5-methylcytosine bases removed from the genomic DNA fragments by 5-methylcytosine deglycosylase are replaced by labeled cytosine in the one or more corresponding positions of the abasic genomic DNA fragments to produce labeled genomic DNA fragments, whereby specific labeling of CpG sequences corresponding to methylated CpG sequences is achieved.