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DNA Amplification for Forensic Analysts

Assessment of Controls

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Known Sample Controls
National Institute of Justice (see reuse policy).

As stated above, negative controls and reagent blanks can greatly assist in the detection of contamination. Positive controls and samples from known sources may also aid in the detection of contamination. Positive controls are single-source samples of a known type; the detection of additional alleles may indicate contamination. Reference samples are expected to be from a single-source, and while the DNA profile may be unknown, results that indicate a mixture could be a sign of contamination.

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