Forensic Biology encompasses the scientific fields of Serology and DNA testing. Serology refers to the processes involved in the identification of body fluids. DNA testing is the isolation, detection, characterization, and interpretation of genetic information. The Forensic Biology section analyzes evidence from a wide variety of crimes including sexual assaults, homicides, robberies, and property crimes. During the Serology examination if analysis indicates possible body fluids, the evidence sample is then forwarded for DNA testing. DNA profiles generated from items of evidence may then be compared to the DNA profile of a person of interest, or be uploaded into CODIS if the necessary criteria are met.
Case and submission details are important and may aid in the determination of what biological examinations are to be performed. Some items of evidence submitted to the Biology unit may also require examination by the Latent Prints, Drug Chemistry, and/or Firearms units. Some of the tests conducted in Biology may interfere with examinations conducted in other units. Knowledge of which sections are and are not examining an item helps guide the examination process, and aids in the preservation of the evidence for testing in other units.
Forensic Biology FAQs
What types of examinations and analyses are performed by the Forensic Biology section?
Blood: Chemical (Phenolphthalein) and immunological (HemaTrace) tests.
Seminal Fluid: Chemical (Acid Phosphatase), microscopic (cellular stain), and immunological (PSA-prostate specific antigen) tests.
Saliva: Chemical (Phadebas) test.
Autosomal DNA testing.
What type of examinations and analyses are not performed by the Forensic Biology section?
Serology: no examinations for the identification of hair, urine, vomit, or feces.
DNA: no DNA testing of hair (with rare exceptions), male specific DNA, mitochondrial DNA, massively parallel/next generation sequencing, or genetic genealogy.
If an item of evidence tests positive indicating the presence of one or more body fluids, does this mean the sample will absolutely contain DNA?
No. There are many components that make up a body fluid. Cells are the only DNA containing component, and the analyses used in the Serology section are often testing for the presence of the non-DNA containing components. Sometimes the presence of a body fluid can be indicated, and the DNA containing cellular component of that body fluid is absent or insufficient to generate a useable DNA result.
Why are reference standards (victim, elimination, suspect) needed for DNA testing?
Reference standards are used for comparison purposes to identify and exclude their DNA profiles from other probative DNA profiles obtained from evidence. Reference standards are necessary when deducing contributors to DNA mixture profiles obtained from evidence items with presumed donors such as intimate samples.
Does the laboratory accept submission of alternate (reference) standards?
On rare occasions and with prior permission from the laboratory alternate standards may be submitted for comparison. Please contact the laboratory to determine acceptable criteria.