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DNA Casework Unit (DCU)

DNA Casework Unit (DCU)

Mission

To provide forensic DNA examinations to the FBI and other duly constituted law enforcement agencies in support of criminal, missing persons, and intelligence cases through evidence testing using forensic serological, mitochondrial DNA, and nuclear DNA methodologies.

The Team

Unit Chief, Forensic Examiners, and Biologists

The Work

Deoxyribonucleic acid (DNA) analysis can occur on body fluid stains and other biological tissues recovered from items of evidence. The DNA testing results obtained from evidence samples are compared to DNA from reference samples collected from known individuals. Such analyses may be able to associate victims and suspects with each other, with evidence items, or with a crime scene. The FBI can conduct nuclear, Y-chromosome, and/or mitochondrial DNA testing on evidence samples as appropriate.

For information regarding the DCU case acceptance policy, click on DCU Case Acceptance Guidance Final (pdf).

In order to expedite DNA testing, please include a completed copy of the DCU Sample Submission form: 2014 DCU Case Submission Form (pdf).

Serology

The DCU performs serological testing to detect and characterize body fluids such as blood and semen on evidence.  Serology testing can identify body fluids for subsequent DNA testing.

Nuclear DNA

Nuclear DNA (nDNA) is the most discriminating and is typically analyzed in evidence containing body fluids, skin cells, bones, and hairs that have tissue at their root ends. The power of nDNA testing lies in the ability to identify an individual as being the source of the DNA obtained from an evidence item, or by excluding an individual as a contributor to the DNA evidence.

Y-chromosome DNA (Y-DNA) testing is a form of nuclear DNA testing that is specific to the male chromosome, also known as the Y-chromosome. This type of testing can be useful for sexual assaults, missing persons, and intelligence cases. The Y chromosome is transmitted from father to son as a complete set; therefore, anyone in the paternal lineage will have the same Y-DNA profile. Because multiple relatives can have the same Y-DNA, unique identifications are not possible from Y-DNA analysis.

Mitochondrial DNA

Mitochondrial DNA (mtDNA) is a form of DNA that is transmitted from mother to child in a complete set; therefore, anyone in the maternal lineage will have the same mtDNA profile. This type of DNA testing can be useful on evidence items such as naturally shed hairs, hair fragments, bones, and teeth. MtDNA analysis is highly sensitivity and may allow scientists to obtain information from items of evidence associated with cold cases, missing persons, samples from mass disasters, and small pieces of evidence containing little biological material. However, because multiple individuals can have the same mtDNA profile, unique identifications are not possible from mtDNA analysis. The DCU also offers kinship analysis and criminal paternity testing as part of criminal, intelligence, and missing person casework. When appropriate, DNA results from evidence relating to criminal cases and missing persons will be uploaded into the National DNA Index System.

If you have any questions about serological and/or DNA testing, please contact us at (703) 632-8446.

For more information on the DCU, click on DCU_Presentation (pdf).