Principles of PCR:

The PCR (polymerase chain reaction) is an extremely easy since immensely powerful methods. It permits enormous amplification of any specific sequence of DNA gives which short sequences either side of it are known. The method is shown in Figure. A polymerase chain reaction reaction contains the goal double-stranded DNA, two primers which hybridize to flanking sequences on opposing strands of the goal, all four deoxyribonucleoside triphosphates and a DNA polymerase. Since, as we shall see, the reaction periodically becomes heated to high temperature, polymerase chain reaction depends upon using a heat-stable DNA polymerase. Several such heat-stable enzymes from thermophilic bacteria bacteria which live in high temperature surroundings are now available commercially. The 1st one used was Taq polymerase from the thermophilic bacterium Thermus aquaticus.