Patent ID: 9523119
Filing Date: 2016-12-20
CPC Classification: C12Q,G01N

Claim Text:
1. A method of distinguishing genotypes of a gene mutation comprising: obtaining an amplification reaction solution which comprises a specimen double-stranded nucleic acid by amplifying a mutation site-including region of a gene contained in a specimen by a nucleic acid amplification reaction; performing a competitive strand displacement reaction by mixing the amplification reaction solution and a reference double-stranded nucleic acid having a specific genotype on the mutation site as well as being labeled with a labeling substance to obtain a reaction solution of the competitive strand displacement reaction and then gradually lowering the temperature of the reaction solution of the competitive strand displacement reaction under a condition to suppress a polymerase extension reaction in which a concentration of EDTA as the extension reaction inhibitor is 25 mM to 50 mM in the reaction solution of the competitive strand displacement reaction, wherein out of the two nucleic acid strands constituting the reference double-stranded nucleic acid, a 3′ terminal site of one strand is labeled with a first labeling substance and a 5′ terminal site of another strand is labeled with a second labeling substance, and at least one of the first labeling substance and the second labeling substance is a fluorescent substance; and assessing a level of an occurrence of strand displacement between the reference double-stranded nucleic acid and the specimen double-stranded nucleic acid by using a ratio of an amount of change in a fluorescence intensity caused by the lowering the temperature of the reaction solution, to an amount of change in a fluorescence intensity caused by lowering the temperature of a control reaction solution which contains the reference double-stranded nucleic acid instead of the specimen double-stranded nucleic acid.