METHOD FOR DISTINGUISHING 5-POSITION METHYLATION CHANGES

摘要

The invention relates to a method for distinguishing 5-position methylation changes of cytosine bases and cytosine-to-thymine mutations and for detecting single nucleotide polymorphisms (SNPs) or point mutations in genomic DNA, comprising the following steps: a) treating a genomic DNA-sample with sulphite or disulphite in such a way that all of the cytosine bases not methylated in the 5-position of the base are changed in such a way as to produce a different base according to the base pairing behaviour while the cytosines which are methylated in the 5-position remain unchanged; b) quantitatively methylating an aliquot of the same genomic DNA sample before chemical treatment according to a) with Sss1 or another methyltransferase; c) testing the two DNA samples treated in this way for the presence of cytosine using the same analytical methods; and d) comparing the cytosine positions that are detected with a reference DNA-sequence.