The PCR (Polymerase Chain Reaction) is a technology using molecular biology discovered in 1985 by Karry Mullis. This method allows the in vitro amplification of a specific region of DNA, in order to produce enough DNA to be adequately tested. .

DNA of different organisms is different (while some genes may be the same, or very similar among organisms, there will always be genes whose DNA sequences differ among different organisms). The DNA sequence (named primer) selected for PCR amplification can be chosen located either on the consensus area of a genus, or of a specie, a serotype…according to the aim of the developing test.

Real Time PCR technology allows a quantification of the target.

Two specific primers bind to the DNA template in a media containing an excess of desoxynucleotides. A Taq polymerase (heat stable DNA polymerase) synthesizes then the complementary strand.

One cycle involves three steps :

* template denaturation of the double-stranded DNA

* primer annealing, which is an important parameter in the success of the PCR experiment.

* primer extension using Taq polymerase

n PCR cycles generate of 2 n DNA copies.