Abstract: To measure the methylation degree of a genomic DNA simply and correctly as well as exhaustively, there is provided a method for amplifying a DNA fragment, characterized by comprising the following steps (1) to (5): (1) digesting a sample double-stranded DNA with a first restriction enzyme; (2) adding a double-stranded DNA fragment consisting of a first oligonucleotide and a second oligonucleotide to a restriction enzyme cleavage end of the double-stranded DNA fragment produced in step (1) to obtain a DNA fragment; (3) digesting the DNA fragment obtained in step (2) with a second restriction enzyme; (4) allowing the double-stranded DNA fragment produced in step (3) to coexist with a third oligonucleotide and a fourth oligonucleotide in the presence of a ligase; and (5) heating the double-stranded DNA fragment obtained in step (4), thereby dissociating the double-stranded DNA fragment and then performing a polymerase chain reaction to selectively amplify a DNA fragment having the cleavage end of the first rest

Abstract: It is an object of the present invention to provide a demethylation method that, from among multiple methylated regions present in the genome DNA of a living cell, can demethylate a specified methylated region only without influencing the other methylated regions, and to achieve the object, a target methylated region present in either a sense or antisense DNA chain in genome DNA of a living cell is demethylated, by artificially generating in the living cell the following (a) RNA comprising a base sequence equivalent to the base sequence of a region comprising all or part of the target methylated region in the DNA chain where the target methylated region is present, or (b) RNA comprising a base sequence equivalent to the base sequence of a region comprising a region neighboring the target methylated region in the DNA chain where the target methylated region is present.

Abstract: The present invention provides a method of identifying a cell, tissue or nucleus, comprising collecting information on the methylation pattern of DNA isolated from the cell, tissue or nucleus and analyzing the resultant information.