Implementation of epigenetics into forensic science: Development of a PCR based multiplex for the simultaneous analysis of age and body fluid identification

As submitted by the proposer:

Recent work on epigenetic methylation for age-based correlations has determined that these markers are cell type specific. Thus, in order to determine a suspects age using epigenetics, one must first determine the body fluid type left at the crime scene.

It is the goal of this proposal to develop an epigenetic multiplex for the simultaneous and trace determination of a suspect’s age and body fluid type that includes semen, vaginal epithelia, saliva and blood.

This project will involve over 120 subjects who will donate blood, saliva, vaginal epithelia or semen. Subjects will also contribute data on their biological age.

First, the researchers will identify and combine a set of body fluid specific age markers into a multiplex for the simultaneous determination of body fluid type and suspect’s age. Second, the researchers will test these markers by analyzing them using a massively parallel sequencer in a manner similar to that used for existing forensic kits. This kit will be validated using SWGDAM guidelines.

The importance of this research should be self-evident to any forensic scientist. Firstly, the determination of tissue type can be critical when levels are too low for conventional serology, or in child abuse where innocent transfer of DNA from skin or sweat from an abuser might be expected to be present on the child, but the presence of semen would not. Secondly, the determination of age is critical as an investigative lead for suspects who are not present in a database.

Once the methylation status is defined in each DNA fragment amplified by the multiplex assay, a software package will be developed to define the cell type and age along with the relative uncertainty in the estimate. The researchers will utilize an approach based on machine learning. The output of the program will define the body fluid type of the DNA recovered from the crime scene, define if a mixture is present, and provide the age of the suspects.

Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14).

ca/ncf