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

First, DNA to be tested heated to
cause the helix to rupture and
polynucleotide chains to be
. Then small synthetic
sequences DNA known as primers
containing nucleotide sequences
similar the sequences of the
of the region to studied
(for example, a containing a
known gene of a given
organism) added. The primers
paired the original DNA in
extremities of the gene be amplified.
Enzymes known polymerases, that
catalyze DNA , and nucleotide
supply are . The primers then are
and the chosen region
replicated. Inthe presence of
primers and more nucleotides of
copies ofthat specific are
generated. (PCR is sensitive even
using a amount of DNA).