SNPs (single nucleotide polymorphisms) detection based on the formation of cholic-acid binding DNA aptamer.

Simple and rapid methods for the detection of single nucleotide polymorphisms (SNPs) are required to analyze the genetic information. We have previously isolated DNA aptamers that bind to cholic acid by an in vitro selection method. A common feature of the sequences of the aptamers was that they included a secondary structure, a three-way junction, in which three stems were connected at the junction. It was also revealed that three-way junctions with fully matched three stems bind cholic acid whereas single-base substitutions at the junction lose binding affinity completely. Here we report a new method for the detection of single nucleotide mutations that is based on the formation of fully matched three-way junctions which bind to cholic acid.