Patent ID: 6977146

Claim:
Method for identifying cytosine methylation patterns in genomic DNA samples, said method comprising the steps of: a) chemically treating a genomic DNA sample in such a way that cytosine and 5-methylcytosine react differently and a different base pairing behavior of the two products is obtained in the duplex; b) enzymatically amplifying portions of the thus-treated DNA sample; c) binding the amplified portions of the thus-treated DNA sample to a surface; d) contacting a set of probes of different nucleobase sequences, each of which contains the dinucleotide sequence 5′-CpG-3′ at least once, to the immobilized DNA samples for hybridization to distinguish methylated and nonmethylated cytosines in said genomic DNA sample; e) removing any non-hybridized probes from the immobilized DNA samples; f) analyzing the hybridized probes in a mass spectrometer, wherein the position of the hybridized probes on the surface permits a classification of the immobilized DNA sample hybridized thereto; g) assigning a peak pattern obtained from the mass spectra to a methylation pattern for the immobilized DNA and comparing the peak pattern with a database to identify cytosine methylation patterns in the genomic DNA sample.