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Home >Criminal Investigation & Forensics > Crime Lab > Lab Services > Forensic Biology

Forensic Biology

The Forensic Biology Section of the Maine State Crime Laboratory analyzes biological fluids and stains recovered as evidence at the scene of crimes. Examination includes biochemical analysis and serological techniques. Once the stain is identified and examined, DNA analysis can be performed. The results of the analysis can be compared to suspects and victims in the case as well as entered into and compared against the CODIS database.

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Deoxyribose nucleic acid, or DNA, is often called the "thread of life" because of its double-helical structure elucidated by Watson and Crick in 1953, as well as its unique ability to carry information. DNA has many interesting properties but three powerful and very unique ones. The first of these is its ability to serve as a model for the production of replicas of itself. The second of these properties is its ability to carry information, which makes it the fundamental molecule of life. Theoretically, the DNA of one cell contains all the information needed to make one person encoded in molecular form. Lastly, the information in DNA is unique to each and every human being, with the exception of identical twins. These three properties enable the Maine State Crime Laboratory to create a unique and individual profile from the molecular DNA left in biological fluids (blood, semen, sweat etc.) recovered from a crime scene. Furthermore, if a suspect is identified in the matter, a comparison may be made between the DNA left at the crime scene and the known DNA of the suspect to either include him(her) as a viable suspect or eliminate them completely. The profile is created from characteristics at 13 different locations, or loci, on the DNA. These locations are variable within the population of Maine, and are not characteristics that are seen or detected without the use of DNA analyzing equipment. The fact that the DNA is non-coding is important because DNA analysis is not used to physically identify the appearance of a suspect, but only to include or exclude a suspect as the perpetrator of a crime.