Polymerase Chain Reaction:

The PCR (polymerase chain reaction) is a biochemical technology in molecular biology to amplify a single or a little copies of a piece of DNA across various orders of magnitude generating thousands to millions of copies of an exacting DNA sequence. It is developed in the year of 1983 through Kary Mullis, PCR is now a general and frequent indispensable method used in biological and medical research labs for a variety of applications. These includes DNA cloning for sequencing and DNA-based phylogeny, the diagnosis of hereditary diseases;  functional analysis of genes; the recognition of genetic fingerprints which is used in forensic sciences and paternity testing and the detection and diagnosis of infectious diseases. In the year of 1993, the Mullis was awarded the Nobel Prize in Chemistry along with Michael Smith for his work on polymerase chain reaction.

The technique relies on thermal cycling consisting of cycles of repeated cooling and heating of the reaction for DNA melting and enzymatic replication of the DNA. The primers short DNA fragments holding sequences complementary to the goal region along with a DNA polymerase (after that the technique is named) are key parts to enable repeated and selective amplification. As the polymerase chain reaction progresses, the DNA produce is itself used as a template for replication setting in motion a chain reaction in that the DNA template is exponentially amplified. Polymerase chain reaction can be broadly changed to perform a broad array of genetic manipulations.