What is the function of a thermal cycler in PCR?

The function of a thermal cycler in the Polymerase Chain Reaction (PCR) is to cycle through specific temperatures to amplify DNA. During PCR, the thermal cycler facilitates the critical steps of denaturation, annealing, and extension.

In the denaturation phase, the thermal cycler heats the reaction mixture to separate the double-stranded DNA into single strands. This is followed by cooling the mixture to allow primers to anneal to the target DNA sequences during the annealing phase. Finally, the cycler raises the temperature again for the extension phase, during which a DNA polymerase enzyme synthesizes new DNA strands by adding nucleotides to the annealed primers. This repetitive cycling through specific temperatures enables exponential amplification of the targeted DNA region.

Thus, the thermal cycler is essential for achieving the precise temperature changes needed for each of these steps, making it crucial for the successful amplification of DNA in PCR.