What is PCR? How does PCR works?

The PCR, polymerase chain reaction, is a method to synthesize many copies of specific regions of a DNA molecule known as target-regions. Its inventor, Kary Mullis, won the Nobel prize for Chemistry in 1993.

First, the DNA designate to test is heated to cause the double helix to rupture and the polynucleotide chains to be exposed. Then the small synthetic sequences of DNA called as primers and containing nucleotide sequences similar to the sequences of the extremities of the region to be studied (for instance, a region containing a known gene exclusive of a given organism) are added. The primers paired with the original DNA in the extremities of the gene to be amplified. Enzymes called as polymerases, that catalyze DNA replication, and nucleotide supply is added. The primers then are completed and the chosen region is replicated. In the presence of additional primers and additional nucleotides millions of copies of that specific region are generated (PCR is very sensitive even using a minimal amount of DNA).