What is the primary function of a thermal cycler in PCR reactions?

The primary function of a thermal cycler in PCR reactions is to cycle through different temperatures. This instrument is designed to precisely control and change temperatures at various stages during the PCR process, which is crucial for DNA amplification. The PCR process involves repeated cycles of denaturation (heating to separate DNA strands), annealing (cooling to allow primers to bind to the target DNA), and extension (raising the temperature to enable the DNA polymerase to synthesize new DNA strands). Each of these steps requires specific temperature conditions, and a thermal cycler automates and ensures these conditions are met accurately and efficiently. This capability enables the rapid amplification of DNA, making it a fundamental tool in molecular biology and genetics research.