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DNA Amplification for Forensic Analysts

Distance Between Two Primers On Target Sequence

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The distance between the 5' ends of the two primers defines the length of the amplicon. In general, primers distanced < 2000 bases apart are used. This allows for sufficient amplification of the target region.

The amplicon length is calculated as:

Product length = (Position of antisense primer - Position of sense primer) +1


The "+1" represents the non-template +A addition by the Taq polymerase

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