1. Introduction
In 1983 Kary B. Mullis was driving through California on a moonlight night (Mullis, 1990). He was pondering how to use DNA polymerase with oligonucleotide primers in order to
identify a given nucleotide at a given position in a complex DNA molecule, such as the human genome. During this drive he invented or discovered the elegant method of making unlimited DNA copies from a single copy of DNA, and called the method: "Polymerase Chain Reaction" (PCR). A couple of months later he conducted the first successful experiment. Ten years after his drive in California, he was awarded the Nobel Prize in Stockholm for his brilliant discovery (Carr, 1993).
PCR was first published in 1985 (Saiki et al., 1985) with Klenow polymerase used as the elongation enzyme. Due to the heat instability of the Klenow polymerase, new enzyme had to be added for every new cycle, and the maximum limit of the product length was 400 bp. In 1988 the first report using DNA polymerase from Thermophilus aquaticus (Taq-polymerase) was published (Saiki et al., 1988). This polymerase greatly enhanced the value of PCR, and the introduction of the automatic programmable heating block in the same report also took the tedious need for three different water baths out of the procedure. Currently the PCR technique is utilized in most molecular biology laboratories as a routine tool which is suitable for performing a great number of different experiments. The method is frequently chosen for conducting experiments, such as cloning, making mutations, sequencing, detecting, typing, etc. (Erlich et al., 1991).
2. Animation
The basic molecular events of PCR are illustrated in an animation of the liquid phase DNA amplification, which is a prerequisite of the solid phase DNA amplification. The whole animation can be seen in the DIAPOPS animation.