Abstract: An object of the present invention is to provide a nucleic acid amplification method for amplifying a desired nucleic acid while suppressing amplification of byproducts in a PCR reaction, a reagent kit used for nucleic acid amplification, a method of detecting single nucleotide polymorphism to detect single nucleotide polymorphism by utilizing that amplification of byproducts is suppressed in a PCR reaction, and a reagent kit used for detecting single nucleotide polymorphism. The method of amplifying nucleic acids by PCR is characterized by admixing in a reaction solution, a homologous recombinant protein which contains at least one of a RecA protein derived from Thermus thermophilus, and a modified RecA protein obtained by modification of the RecA protein and having a function similar to that of the RecA protein, and carrying out PCR.

Abstract: An object of the present invention is to provide a nucleic acid amplification method for amplifying a desired nucleic acid while suppressing amplification of byproducts in a PCR reaction, a reagent kit used for nucleic acid amplification, a method of detecting single nucleotide polymorphism to detect single nucleotide polymorphism by utilizing that amplification of byproducts is suppressed in a PCR reaction, and a reagent kit used for detecting single nucleotide polymorphism. The method of amplifying nucleic acids by PCR is characterized by admixing in a reaction solution, a homologous recombinant protein which contains at least one of a RecA protein derived from Thermus thermophilus, and a modified RecA protein obtained by modification of the RecA protein and having a function similar to that of the RecA protein, and carrying out PCR.

Abstract: The present invention provides a method of constructing a circular DNA library having an increased content of a desired first dsDNA by removing a second dsDNA using RecA protein to introduce a target single strand nucleic acid by homologous recombination at the 3? terminal portion of the second dsDNA, whereby the target DNA has a 3? terminal portion that differs from the 3? terminal portion of the second dsDNA to prevent circularization, thereby creating a triple stranded DNA portion at the 3? terminal end of the second dsDNA, adding Exonuclease I to digest the displaced first strand of the second dsDNA, ligating the DNA fragments to circularize the desired first dsDNA, removing the linear second dsDNA, thereby constructing the circularized DNA library having an increased content of the desired first dsDNA.

Abstract: An object of the present invention is to provide a nucleic acid amplification method for amplifying a desired nucleic acid while suppressing amplification of byproducts in a PCR reaction, a reagent kit used for nucleic acid amplification, a method of detecting single nucleotide polymorphism to detect single nucleotide polymorphism by utilizing that amplification of byproducts is suppressed in a PCR reaction, and a reagent kit used for detecting single nucleotide polymorphism. The method of amplifying nucleic acids by PCR is characterized by admixing in a reaction solution, a homologous recombinant protein which contains at least one of a RecA protein derived from Thermus thermophilus, and a modified RecA protein obtained by modification of the RecA protein and having a function similar to that of the RecA protein, and carrying out PCR.

Abstract: An objective of this invention is to provide a method which can specifically enrich a desired DNA with a long insert size from a DNA library and can provide a clone of the DNA directly. This invention provides a method of constructing a DNA library having increased proportion of a first double-stranded DNA therein by removing, from an original library containing the first double-stranded DNA to be increased in proportion, a second double-stranded DNA different from the first double-stranded DNA.

Abstract: An objective of this invention is to provide a method for detecting DNA polymorphism that has high sensitivity and efficiency and does not need long DNA searching region. A homologous recombination protein RecA makes partial triple strand DNA from target double DNA and oligonucleotide probe complementary to the DNA. The triple strand DNA maintains stable triple strand DNA after RecA protein is removed. The present inventors found that the thermostability of triple strand DNA changes greatly when there is a mismatch between target DNA and oligonucleotide probe because of the existence of polymorphism in the target DNA. Utilizing this change of thermostability, efficient detection of polymorphism in labeled DNA is possible by examining whether oligonucleotide probe is released and the triple strand DNA is solved after heat treatment of triple strand DNA formed using homologous recombination protein.

Abstract: The present invention provides a method of constructing a circular DNA library having an increased content of a desired nucleic acid by removing a specific DNA from the circular DNA library by using a RecA protein. More specifically, the present invention provides a method of constructing a DNA library having an increased content of the first dsDNA by removing a second dsDNA different from the first dsDNA from a DNA library containing the first dsDNA to be increased in content and the second dsDNA.

Abstract: The present invention provides a method of constructing a DNA library having increased proportion of a desired nucleic acid(s) therein by removing a nucleic acid(s) other than the desired nucleic acid(s) from a parent library.

Abstract: An objective of this invention is to provide a method which can specifically enrich a desired DNA with a long insert size from a DNA library and can provide a clone of the DNA directly. This invention provides a method of constructing a DNA library having increased proportion of a first double-stranded DNA therein by removing, from an original library containing the first double-stranded DNA to be increased in proportion, a second double-stranded DNA different from the first double-stranded DNA.

Abstract: The present invention provides a method of constructing a DNA library having increased proportion of a desired nucleic acid(s) therein by removing a nucleic acid(s) other than the desired nucleic acid(s) from a parent library.

Abstract: A nucleic acid detecting method using a probe is provided which makes it possible to obtain correct information on a target double-stranded DNA dsDNA without damaging the target double-stranded DNA dsDNA. In the nucleic acid detecting method of the present invention, a nucleic acid is detected by subjecting the target double-stranded DNA dsDNA bound with a first single-stranded DNA dsDNA probe via recA protein to a treatment with a single-stranded DNA dsDNA specific nuclease, to thereby allow a second single-stranded DNA dsDNA probe consisting of a base sequence complementary to that of the first probe or a part thereof and labeled with a detectable marker to bind to the target DNA dsDNA.

Abstract: This invention provides a hairpin-shaped nucleic acid probe which is capable of forming stable hybrid with target nucleic acid, and a method for detecting nucleic acid containing a sequence complementary to a part of sequence of the probe. After contacting RecA to a hairpin-shaped single strand probe for hybridization, this complex is contacted with a target nucleic acid to form a triplex recombination intermediate using RecA function. After ligating the probe and the target nucleic acid, the target nucleic acid is detected by the label on the probe.