0It is a revolutionary method developed by Kary Mullis in the 1980s, used to synthesize a new strand of DNA complementary to the offered template strand.
Components of PCR:
1. DNA template- the DNA strand that contains the target sequence which has to be multiplied.
2. DNA Polymerase enzyme- a type of enzyme that synthesizes new strands of DNA complementary to the target sequence. The first and most commonly used of these enzymes is Taq DNA polymerase (from Thermus aquaticus), whereas PfuDNA polymerase (from Pyrococcus furiosus) is used widely because of its higher fidelity when copying DNA.
3. Primers- a short sequence of nucleotides that provides an initiation point for DNA synthesis.
4. dNTPs(deoxynucleotides triphosphates)- single units of the bases A, T, G, and C, which are essentially "building blocks" for new DNA strands.
Steps in PCR:
1. Denaturation (96°): Heat the reaction strongly to separate, or denature, the DNA strands. This provides a single-stranded template for the next step.
2. Annealing (55°C-65°C): Cool the reaction so the primers can bind to their complementary sequences on the single-stranded template DNA.
3. The extension (72°): Raise the reaction temperatures so Taq polymerase extends the primers, synthesizing new strands of DNA.
