The Chain Reaction (PCR) is a laboratory technique that permits copying in vitro of specific DNA sequences and has revolutionized the field of molecular biology. Conceptually, the PCR is a simple technique is to heat the separation of the two strands of DNA to be amplified is, and a copy simultaneously from a point determined by an artificial DNA fragment called primer, through the action of an enzyme called DNA polymerase. The result is a doubling of the number of molecules of a particular sequence of DNA. This process is repeated a number of times or cycles, such as 30, and achieved an increase or exponential amplification of the number of copies of template DNA fragment. (more...)