Date of Award

Spring 6-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department/Program

Forensic Science

Language

English

First Advisor or Mentor

Mechthild Prinz

Second Reader

Patrick McLaughlin

Third Advisor

Grace Axler-DiPerte

Abstract

Trace DNA has proved to be a reliable forensic tool when investigating crimes. Current methods of trace DNA recovery from fabric include cutting, swabbing, scraping, and tape lifting. A dry vacuum collection method originally developed for paper evidence is an alternative nondestructive option for DNA collection from fabric. This research evaluated the success of the dry vacuum technique on pieces of cotton fabric that had been briefly touched as well as the effectiveness of different moistening agents and filters. The samples were designed to simulate an assault with the suspect grabbing the clothing of their victim. Volunteers created samples by rubbing their faces, rubbing their hands together, and gripping clean 15 cm x 15 cm cotton fabric squares. Four fabric samples and one buccal swab were collected per donor. The fabric was then vacuumed using either an irradiated glass pipette fit with a Puritan cotton swab moistened with water, 10% Tween-20, or an irradiated plastic pipette tip with the filter moistened with water or 10% Tween-20. After DNA extraction and quantitation, it was observed that quantities from each donor varied however the dry vacuum technique collected a sufficient amount of touch DNA for DNA analysis from all donors. Water as a moistening agent yielded a higher amount of DNA. There was no difference when using a glass pipette versus a plastic pipette tip. The dry vacuum method is an efficient non-destructive method which can be implemented in any DNA laboratory that has a vacuum pump or bench vacuum outlet.

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