Polymerase chain reaction, also known as gene amplification, was developed by Kary B. Mullis to make multiple copies of specific DNA in an artificial medium. PCR can detect the pathogens (bacteria or virus) at very low concentrations by the amplification of nucleic acids even before the development of the symptoms. Few uses of PCR:
(i) PCR can detect HIV in suspected patients of AIDS.
(ii) PCR can detect mutations in genes in suspected patients of cancer.