Patent ID: 8309305

Claim:
A method for discriminating between the nucleotide sequence of a first nucleic acid and the nucleotide sequence of a second nucleic acid in a nucleic acid sample, the method comprising the steps of: (i) providing a reaction solution, comprising at least one type of deoxynucleotide triphosphate, a DNA polymerase having a strand displacement ability, the nucleic acid sample as a template, an oligonucleotide primer (1) and an oligonucleotide primer (2), and an oligonucleic acid (hereinafter “mask oligo”); (ii) incubating the reaction solution under isothermal conditions to carry out a polymerase reaction and to produce an amplification product thereof; (iii) detecting the amplification product and measuring an amplification rate of the amplification product; and (iv) using the measured amplification rate as an indicator to discriminate between the nucleotide sequence of the first nucleic acid and the nucleotide sequence of the second nucleic acid in the nucleic acid sample, wherein the oligonucleotide primer (1) is more complementary to the first nucleic acid than to the second nucleic acid, and the oligonucleotide primer (2) hybridizes to a portion of an elongation product of the oligonucleotide primer (1), wherein said portion is located 3′ downstream of the nucleotide sequence of the oligonucleotide primer (1) in said elongation product, wherein the mask oligo hybridizes to the nucleotide sequence portions of the first nucleic acid and the second nucleic acid to be discriminated, wherein the mask oligo is more complementary to the second nucleic acid than to the first nucleic acid, wherein the mask oligo does not become an origin of an elongation reaction with the polymerase for any nucleic acid template, and wherein a portion of the oligonucleotide primer (1) and a portion of the mask oligo hybridize to the same nucleotide sequence portions of the first nucleic acid and the second nucleic acid.