DNA polymerases as engines for biotechnology.

This review examines the DNA polymerases, a class of enzymes that has been an essential tool for molecular biology research. Several families of DNA polymerases have been defined based on amino acid sequence comparisons, and new enzymes are continually being discovered, driving the expansion of the current classifications. Structural similarities among the enzymes are examined, as well as the functions of the various subunits and enzyme domains. The natural variety of polymerase activities has been harnessed for applications such as amplification, labeling, and detection of DNA sequences. In addition, enhancements to DNA polymerases by genetic engineering will be described, such as enzymes specifically designed for DNA sequencing by improving the incorporation of dideoxynucleotide terminators. Reverse transcription, the ability to use RNA as a template for DNA synthesis, is described for the application of making cDNA. We believe that new and unanticipated applications will emerge as new polymerases and mutated polymerases are created and characterized.