Keywords

Touch DNA; Touch Deposits; Forensic Biology; DNA; Forensics; Trace Evidence

Abstract

Locard’s exchange principle states that every contact leaves a trace. When someone touches a surface or object, they leave a touch deposit. Touch deposits are composed of epithelial cells and random debris from the toucher’s fingers that have been shed onto the contacted surface. This is useful when a fingerprint isn’t distinct enough to be collected; DNA could be recovered instead to create a genetic profile. This project focuses on discovering how cells in each touch deposit are suitable for genetic analysis using micromanipulation techniques and understanding patterns between type of touch and quality of genetic profile. The micromanipulation technique is done using a water-soluble adhesive and a tungsten needle to isolate and collect individual and grouped cells that might be useful for these types of samples. These tools under a microscope allow the skin cells to be separated from the larger sample and individually transferred into tubes for downstream biochemical reactions, including quantification and profiling. While micromanipulation is a technique that has been successful in methods involving epithelial cells, the validity of its use when applied to touch DNA cells, which are in less pristine condition than most samples due to the nature of touch deposits, is still being evaluated. The micromanipulation of grouped cells resulted in more probative genetic profiles and fewer drop-ins, despite inconclusive nucleation, in comparison to individually collected, nucleated cells.

Thesis Completion Year

2024

Thesis Completion Semester

Summer

Thesis Chair

Ballantyne, Jack

College

College of Sciences

Department

Chemistry

Thesis Discipline

Forensic Science

Language

English

Access Status

Campus Access

Length of Campus Access

1 year

Campus Location

Orlando (Main) Campus

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Rights Statement

In Copyright