Polymerase chain reaction (PCR) assays are a commonly used molecular biology technique for amplifying and detecting specific DNA sequences. PCR assays are used in various fields, including diagnostics, forensics, and research. The process involves amplifying a specific DNA sequence by repeatedly heating and cooling the reaction mixture to denature, anneal, and extend the DNA strands. This results in exponential amplification of the target DNA sequence, which can then be detected using various methods, such as gel electrophoresis or real-time PCR. PCR assays are highly sensitive, specific, and can be used to detect even small amounts of DNA. They are a powerful tool for studying genetic variations, identifying pathogens, and diagnosing genetic diseases.