Defense Date
2024
Document Type
Directed Research Project
First Advisor
Stephanie Walcott
Second Advisor
Dr. Christopher Ehrhardt
Third Advisor
Katherine M. Philpott
Fourth Advisor
Jody H. West
Abstract
Fired cartridge cases are a common type of evidence submitted to forensic DNA profiling but are challenging to analyze because they usually contain only trace amounts of biological material. As such, there is a significant need in caseworking units for new screening techniques to determine if biological material is present and is in high enough quantity to attempt DNA profiling. The goal of this study was to test a new method for quickly visualizing biological material on cartridge cases. Biological deposits were created by handling fired and unfired cartridge cases through a series of conditions. The biological material was collected using different types of swabs and sampling procedures and then assessed through a combination of conventional DNA profiling and fluorescently labeled dyes to visualize the cells directly. Results showed that of the three swabs tested, the fewest cells were eluted from cotton swabs, while similar number of cells were eluted from the nylon and foam swabs. Additionally, there was no clear correlation between the number of cells and DNA yields. The addition of bovine serum albumin and Gly-Gly-His tripeptide (GGH tripeptide) did not improve the DNA yields remarkably. The use of two foam swabs did not improve cell counts or DNA yield compared to the foam and cotton swab combination. There were fewer cells eluted from swabs of fired cartridge cases compared to unfired cartridge cases.
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
11-3-2024