02. Thermostable Ligase
A Cystic Fibrosis Diagnostic Technology
Francis Barany
A key tool of the biotechnology industry is a polymerase chain reaction (PCR) using thermostable DNA polymerase. PCR amplifies DNA based on specific sequences at either end of a region of interest, but in itself provides no information about the middle of the region. Laborious subsequent steps need to be performed in order to determine if the region is mutated and to identify those mutations. Francis Barany, Microbiology and Immunology, Weill Cornell Medical College, isolated and cloned a different thermostable enzyme, a ligase, and developed an assay dubbed ligase chain reaction (LCR) that both amplifies DNA and discriminates single-base substitutions in a region of interest. LCR can be combined with additional methods to identify other large-scale genetic mutations. The method, enzyme, and several subsequent elaborations have been licensed to Applied Biosystems, Inc. The company has developed two products from this technology: a diagnostic for cystic fibrosis and the SNPlex™ Genotyping System.