What is PCR?
Polymerase chain reaction (PCR) A method for amplifying a DNA base sequence using a heat-stable polymerase and two 20-base primers, one complementary to the (+) strand at one end of the sequence to be amplified and one complementary to the (-) strand at the other end. Because the newly synthesized DNA strands can subsequently serve as additional templates for the same primer sequences, successive rounds of primer annealing, strand elongation, and dissociation produce rapid and highly specific amplification of the desired sequence. PCR also can be used to detect the existence of the defined sequence in a DNA sample.
PCR is an acronym which stands for polymerase chain reaction . The PCR technique is basically a primer extension reaction for amplifying specific nucleic acids in vitro. The use of a thermostable polymerase allows the dissociation of newly formed complimentary DNA and subsequent annealling or hybridization of primers to the target sequence with minimal loss of enzymatic activity. PCR will allow a short stretch of DNA (usually fewer than 3000 bp) to be amplified to about a million fold so that one can determine its size, nucleotide sequence, etc. The particular stretch of DNA to be amplified, called the target sequence, is identified by a specific pair of DNA primers, oligonucleotides usually about 20 oligonucleotides in lenth. PCR has revolutionized molecular genetics and continues to be applied to many fields of biology.
