The polymerase chain reaction is the technology used in molecular biology that is used to amplify the single or few copies of the DNA pieces across different orders of the magnitudes, producing millions of copies of a specific DNA sequence. The polymerase chain reaction was first developed by Kary Mullis in 1983 which has become quite common now as an important method to be used in biological and medical research for a number of applications. These include DNA based phylogeny, DNA cloning for the sequencing, and functional evaluation of genres, the hereditary disease diagnosis, detection of genetic finger prints and infectious diseases.
The method is based on thermal cycling, consisting of the repeated cycles of heating and cooling of the reaction for the DNA melting and enzymatic copy of the DNA. Primers, which are little DNA fragments, having the sequences complementary to the target site along with the DNA polymerase, which the method is labeled after are major elements to enable repeated and selective applications. As the technology of the PCR got advancer, the DNA produced is itself utilized as the template for the replication, making the motion in chain reaction where the DNA template is amplified exponentially. PCR can also be extensively changed to make a wide range of genetic manipulations.
Almost all the PCR applications use a heat stable DNA polymerase, like Taq polymerase, which is the enzyme that is typically, separated from the bacterium Thermus aquaticus. This DNA polymerase enzymatically makes the new DNA strand from the DNA building blocks, the nucleotides, by applying the single stranded DNA as the template and the DNA oligonucleotides which are needed for triggering the DNA synthesis. Most of the PCR modes utilize thermal cycling that is the alternate cooling and heating of the PCR sample through a particular series of temperature phases.