[PCR--polymerase chain reaction. Principles and applications in research and medical practice].

At present, PCR (polymerase chain reaction), is the method most often used in molecular genetics. The aimed amplification of the short DNA chain is reached by three cyclically repeated steps using different temperatures. The reaction demands the presence of DNA polymerase, buffer, dNTP as basic elements of DNA and a pair of short oligonucleotides, which makes the reaction specific. The product of reaction is usually analysed using electrophoresis in agarose gel or polyacrylamide gel and visualised by ethidium bromide.