U.S. flag

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

How It Got There: Associating Individual DNA Profiles with Specific Body Fluids in Mixtures Using Targeted Digital Gene Expression and RNA-SNP Identification

NCJ Number
Date Published
September 2018
12 pages
This report details research into recognizing specific DNA profiles in bodily fluids and applying investigative techniques to determine how the DNA profile was deposited on a particular substrate (i.e. how did it get there?).

The recovery of a DNA profile from the perpetrator in criminal investigations provides valuable source level information for investigators. However, a DNA profile does not reveal the circumstances by which biological material was transferred. This contextual information (activity level) can be obtained by a determination of the tissue or fluid source of origin of the biological material as it indicates some behavioral activity on behalf of the individuals that resulted in its transfer from the body. The purpose of this project was to provide investigative information to develop body fluid identification methods or analytical platforms that could evolve into a commercial body fluid identification product for DNA analysis in crime laboratories. The research sought to establish and validate a molecular based method for body fluid identification that is capable of identifying, and distinguishing between, all of the commonly encountered body fluids and tissues (blood, semen, saliva, vaginal secretions, menstrual blood, and skin). Secondly, the research sought to establish probative objective activity level information for criminal investigations. The sequencing assays developed during this research provide activity level information in criminal investigations and the ability to associate a DNA profile to a specific body fluid or tissue in admixed samples. These assays could be developed into a commercial product for use in crime laboratories.

Date Published: September 1, 2018