PCR, a technique used to amplify a segment of DNA of interest into million copies. The technique just mimics what happens during DNA replication. The process requires a segment of the DNA of interest, specific DNA primers, heat resistant DNA polymerase enzymes(eg Taq polymerase), a pool of DNA nucleotides and salts that are required to create a suitable environment for enzymes. The process involves the isolation of the DNA of interest, denaturation of the DNA double helix into single strands by high temperatures, annealing of the specific DNA primers to specific sequences on DNA single strands through lowering temperatures, and elongation of the new DNA strands where the DNA of interest act as a template for synthesis of new DNA strand. The cycle is repeated several times by means of raising the temperature and then lowering the temperature.