RT-PCR and alternative methods to PCR for in vitro amplification of nucleic acids.

The amplification of small amounts of nucleic acids via PCR (Mullis and Faloona, 1985) has undergone a tremendous development in biology, biochemistry, clinical diagnosis, and related fields. The typical three step reaction consisting of heat denaturation, primer annealing, and primer elongation together with the advanced technology in the instrumentation of thermal cyclers has made the reaction simple and fast. The idea to use a heat stable DNA polymerase, primers, and dNTPs in order to amplify double stranded DNA molecules in an exponential manner is not the only way to produce large amounts of nucleic acids starting from a few molecules only. This paper will give an overview of some alternatives and their applications.