Ligase Chain Reaction (LCR) is a laboratory-based molecular biology technique used for the specific detection and amplification of a target DNA sequence. It is a sensitive method that allows for the identification and analysis of specific DNA fragments, making it useful in numerous research and diagnostic applications.
LCR involves the use of a DNA ligase enzyme, which has the ability to join or ligate two DNA fragments together. In this technique, two sets of specially designed oligonucleotide primers are used, each binding to opposite strands of the target DNA sequence. The primers are positioned in such a way that they will only bind to the target DNA if it contains the specific sequence being sought.
The reaction starts with the denaturation of the DNA sample, separating it into single strands. The primers then anneal to their complementary regions on the target DNA. The ligase enzyme is added to the mixture, and if the target DNA is present, the ligase will efficiently join the primers together, forming a circular DNA molecule.
The LCR procedure is subjected to repeated cycles of denaturation, primer annealing, and ligation, resulting in the exponential amplification of the target DNA. The amplified products can be detected and analyzed using various methods, such as gel electrophoresis or fluorescent labeling.
LCR is highly specific, as it requires exact complementary sequences for primer annealing and ligation. Thus, it offers great accuracy and reliability in identifying and quantifying specific DNA sequences, making it a valuable tool in fields such as medical research, genetic testing, and forensic analysis.
