The PCR (polymerase chain reaction) is a biochemical technology in molecular biology to intensify a one or a little copies of a piece of DNA across several orders of magnitude generating thousands to millions of copies of an exacting DNA sequence. It is developed in the year of 1983 by Kary Mullis, PCR is now a common and frequent indispensable method used in biological and medical research labs for several of applications. These contains 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.