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Principles of Forensic DNA for Officers of the Court

DNA Detection

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After the DNA molecules have been separated by electrophoresis, the different DNA types, or alleles, must be detected. As a result of the amplification process, the different STR loci are prelabeled with different colored fluorescent dyes. Their respective alleles are detected by a laser that scans across the slab gel or capillary. On a slab gel, this is sometimes seen as colored bands that are captured in a digital image. An electropherogram, which is a recording of colored peaks, is produced on the CE instrument and some slab gel systems.

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