Polymerase Chain Reaction

Abstract

Polymerase chain reaction or PCR is a method of multiplying DNA copies and was invented in 1983. This process depends on denaturation of DNA at high temperatures, annealing of primers to the DNA, and elongation and synthesis of new DNA strands by the heat-resistant Thermophilus aquaticus polymerase. It utilizes nucleotides and magnesium chloride as a cofactor. PCR can generate more than 30 billion copies of DNA in a couple of hours. Its advanced method, real-time PCR (RT-PCR), can quantify simultaneously while multiplying the DNA and is, hence, also known as quantitative PCR (qPCR). It uses fluorescence-emitting dyes such as SYBR green and TaqMan to quantify DNA multiplication. PCR is used in forensics to multiply DNA evidence, in diagnosing genetic diseases and mutations from body fluids like saliva and blood, and in genetic engineering.