1) A procedure that produces multiple copies of a short segment of DNA through cycles of: 1) denaturation (heat-induced separation of double-stranded DNA into single strands); 2) annealing (binding of specific primers on either end of the target segment); and 3) elongation (extension of the primer sequences over the target segment with DNA polymerase). The amplified product, doubled each cycle for 30 or more cycles, can then be subjected to further testing.

2) Polymerase chain reaction (PCR) is a laboratory technique used to amplify DNA sequences. The method involves using short DNA sequences called primers to select the portion of the genome to be amplified. The temperature of the sample is repeatedly raised and lowered to help a DNA replication enzyme copy the target DNA sequence. The technique can produce a billion copies of the target sequence in just a few hours.