Date of Submission

5-2023

Document Type

Thesis

Degree Name

Master of Science in Forensic Science

Department

Forensic Science

Advisor

Heather M. Coyle, Ph.D.

Committee Member

Josep De Alcaraz-Fossoul, Ph.D.

Committee Member

Sushmita Ghosh, Ph.D.

Keywords

Trace DNA, Recovery Techniques, Diamond Dye

MeSH

DNA

LCSH

DNA--Analysis

Abstract

This study aspires to find a new screening approach to trace DNA recovery techniques to yield a higher quantity of trace DNA from larger items of evidence. It takes the path of visualizing trace DNA on items of evidence with potential DNA so analysts can swab a more localized area rather than attempting to recover trace DNA through the general swabbing technique currently used for trace DNA recovery. The first and second parts consisted of observing trace DNA interaction with Diamond Dye on porous and non-porous surfaces.

The third part involved applying the Diamond Dye solution by spraying it onto brand new and laundered brassieres that had trace DNA placed by donors on the cup and clasp areas. The stained brassieres were then visually analyzed using a Canon T8i camera and EF-S 60 mm macro lens under 455nm alternate light and a 550nm emission filter to locate areas that fluoresced, meaning that trace DNA is present, and images were captured for record. The final part of the study consisted of swabbing laundered brassieres that donors deposited trace DNA onto using the blind double swabbing and Diamond Dye-localized double swabbing techniques on the cup and clasp areas.

The swabs were put through DNA extraction via the Qiagen’s QIAamp Investigator kit and quantification via Thermo Fisher’s Quantifiler Trio then analyzed for the quantity of DNA present. The data was separated into swab techniques and the data was compared using an independent t-test at 95% confidence. The one-tail analysis determined a p-value of 0.0883 with the goal being a p-value of less than 0.05. Statistically, the results show that there is not a significant difference in the amount of trace DNA retained based on whether the DNA is visualized before proceeding with double swabbing.

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