The polymerase chain reaction (PCR) capitalizes on this biological toolbox by manufacturing millions of copies of desired piece of DNA. Invented in 1985 by Kary Mullis, Henry Erlich, and their colleagues at Cetus Corp. of Emeryville, Calif. (Science, 230: 1350-4), the technique has had an enormous impact on the field of biotechnology. Cetus joined with the Norwalk, Conn.-based Perkin-Elmer Corp. to form Perkin-Elmer Cetus Instruments, which markets PCR. The process has been patented by Perkin-Elmer Cetus, but other companies are quickly developing alternative methods of replicating DNA, expanding the approach and its possibilities even further.
The polymerase chain reaction rapidly replicates a selected piece of DNA in test tube. The recipe includes a target DNA sequence; two synthetic, single-stranded oligonucleotide primers that are complementary to opposite ends of the target sequence; a hefty supply of the four types of DNA nucleotide building blocks; and most important , Taq1, a DNA ...