Method for determining polymorphism

A method of detecting a single-nucleotide replacement, comprising:

• 1) hybridizing a sample DNA including a single-nucleotide replacement site with a plurality of types of DNA probes, having a complementary sequences to sequences contained in the sample DNA, wherein each of the DNA probes is labeled with a different marker substance at a nucleotide that pairs up with the nucleotide of the single-nucleotide replacement site, the different marker substances generating light of different wavelengths depending on a pattern of the nucleotide corresponding to the single-nucleotide replacement site;
• 2) reacting a DNA strand, a part of which is double stranded, obtained in step 1), with a nucleic acid synthesizing enzyme having a repair function;
• and
• 3) optically measuring micro-movement of the marker substance at a plurality of points in a lapse of time in the reaction of step 2).