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CONTAMINATION

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  282

2026-08-04

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CONTAMINATION

If care is not used in DNA extractions and typing, then biologic material from an extraneous source, such as the evidence technician, scientist, or laboratory technician, can be introduced accidentally. This can be a serious problem, especially with PCR-based methods, because the DNA from the contamination may also be amplified and can overwhelm the DNA from the sample. In most cases, sufficient biological material is present to provide enough DNA so that the problem occurs only rarely; however, there has been an increase in recent years because of the smaller amounts of biologic material needed to determine a DNA type. Forensic biology laboratories take extraordinary steps and precautions to minimize contamination and detect it if it occurs. For example, DNA extraction is performed in a completely different environment than amplification.