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Steps involved in PCR process:

  1. PCR process is a cycle of three successive reaction:
    1. Denaturation:
  • At 93 - 95°C, the target DNA molecule is denatured, and two strands of DNA is separated.
  1. Primer Annealing:
  • In this step a short synthetic DNA primers are annealed to the separated strands.
  • At this point the temperature must be low enough for the process of hybridisation. It must be around 50 - 70°C.
  1. DNA Synthesis:
  • Here polymerisation process is proceeding in presence of the enzyme DNA polymerase.
  • The temperature should be about 70 - 75°C.

PCR - Polymerase Chain Reaction process

  1. The above three steps are repeated of 25 - 30 cycles.
  2. At the end of 20 cycles the number of newly synthesized DNA is 1 × 106 and after 30 cycles its 1 × 109.
  3. This number can be calculated by the below formula:
    Mf = Mi × 2n
    Mf = initial number of molecules (templates)
    Mi = final number of newly synthesized DNA molecules by PCR
    n = number of cycles took place