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Principles of Forensic DNA for Officers of the Court

STR Amplification

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Amplification uses the PCR process to create copies of specific DNA target regions from the original sample. The STR amplification process also incorporates chemical labels (e.g. fluorescent dyes) for subsequent detection of target alleles.

The actual procedure involves the heating and cooling of samples in a specific pattern in an instrument called a thermal cycler. After approximately 30 cycles, a 'PCR Product' (amplicon or amplified product) is created and subsequently tested.

Animated illustration of DNA strand on copy machine, making copies.
National Institute of Justice (NIJ) (see reuse policy).

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