Reaction, polymerase chain (PCR)

Reaction, polymerase chain (PCR): A key technique in molecular genetics that permits the analysis of any short sequence of DNA (or RNA) without having to clone it. PCR is used to amplify selected sections of DNA, something that used to be done in bacteria, a process that took weeks, but with PCR in a test tube it takes only a few hours. PCR is highly efficient so that untold numbers of copies can be made of the DNA. The PCR technique has innumerable uses -- to diagnose genetic diseases, do DNA fingerprinting, find bacteria and viruses, study human evolution, clone the DNA of an Egyptian mummy, etc. PCR has become an essential tool for biologists, DNA forensics labs, and many other labs wishing to study the genetic material. PCR was discovered by the American biochemist Kary B. Mullis. At the time Dr. Mullis (1944-) thought up PCR in 1983, he was working at Cetus, one of the first biotechnology companies, in Emeryville, California. There he was charged with making short chains of DNA for other scientists. Mullis has written that he conceived of PCR while cruising along the Pacific Coast Highway 128 one night on his motorcycle. He was playing in his mind with a new way of analyzing mutations in DNA when he realized that he had instead invented a method of amplifying any DNA region. Mullis has said that before his motorcycle trip was over he was already savoring the prospects of a Nobel Prize. Mullis left Cetus in 1986. He did no further research and published no further scientific work. According to Dr. Paul Rabinow, who wrote a 1996 book titled "Making P.C.R.", Mullis is "a tinkerer, a bricoleur, he loves to play with things, he loves to try things out, he ignores people who say you can't do it....He was an experimentalist not in the high scientific sense but the magician sense." Dr. Mullis shared the Nobel Prize in chemistry with Michael Smith in 1993.