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Polymerase chain reaction principal steps

Denaturation: Double strand of DNA is separated into 2 strands by heat. Annealing: Two rows of nucleotides are “primed” by the addition of 2 short strands (oligonucleotides designed to bind specifically on either side of the section of gene of interest). Extension: The polymerase enzyme synthesizes a copy of the nucleotide sequence between the primers in the form of a new double strand. This process is repeated, and at each stage, the number of copies doubles. (Contributed by Dr. K K Jain.)