U.S. flag

An official website of the United States government, Department of Justice.

Principles of Forensic DNA for Officers of the Court

DNA Detection

Home  |  Glossary  |  Resources  |  Help  |  Contact Us  |  Course Map

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.

Back Forward