Ligase chain reaction

The ligase chain reaction (LCR) is a method of DNA amplification. While the better-known PCR carries out the amplification by polymerizing nucleotides, LCR instead amplifies the nucleic acid used as the probe. For each of the two DNA strands, two partial probes are ligated to form the actual one; thus, LCR uses two enzymes: a DNA polymerase (used for initial template amplification and then inactivated) and a thermostable DNA ligase. Each cycle results in a doubling of the target nucleic acid molecule. A key advantage of LCR is greater specificity as compared to PCR.