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PCR analysis

The result of a PCR experiment is millions of copies of the DNA region flanked by the primers. The size of the amplified fragments will then be determined by the primers. For example, in the image below, PCR product A will be 200 bp, PCR product B will be 900 bp long, C will be 700 bp and D 400 bp.

To visualize these fragments other techniques such as gel electrophoresis need to be utilized.

A diagram showing four pairs of complementary DNA strands and the resulting products after PCR. The DNA fragment pairs are labelled A through D, and the fragments are all 1000 base pairs long. Each pair of DNA fragments shows two primers, a forward primer in the 3 prime to 5 prime direction and a reverse primer in the 5 prime to 3 prime direction. The primers are spaced differently in each pair, and the base pairs between the two primers are what will be included in the fragments after PCR. On the right, each fragment is shown after PCR: fragment A has a length of 200 base pairs, the forward primer is located at 200 base pairs and the reverse primer is located at 400 base pairs. Fragment B is 900 base pairs long. The forward primer is located at 50 base pairs and the reverse primer is located at 950 base pairs. Fragment C is 700 base pairs long. The forward primer is located at 20 base pairs and the reverse primer is located at 720 base pairs. Fragment D is 400 base pairs long. The forward primer is located at 220 base pairs and the reverse primer is located at 620 base pairs.

Figure 1. PCR Products

Referred from:

Article
PCR (Polymerase Chain Reaction)
Article
Polymerase Chain Reaction Simulation