Date of Submission

5-2024

Document Type

Thesis

Degree Name

Master of Science in Forensic Science

Department

Forensic Science

Advisor

Ashley G. Morgan, Ph.D.

Committee Member

Jaime M. Ullinger, Ph.D.

Committee Member

Heather M. Coyle, Ph.D.

Keywords

Nuclear DNA, Decomposition, Skeletal Remains, Freshwater

MeSH

DNA, Body Remains

LCSH

DNA--Analysis, Human decomposition, Dead, Fresh water

Abstract

This research compared freshwater and dry decomposition environments and their impact on DNA recovery from Sus scrofa domesticus(domestic pig) femora over a 3-month period. Prior to decomposition, initial cuttings were taken from "fresh" bone samples. Cuttings were then collected at 3-week intervals from waterlogged and dry bone samples. All samples were extracted using the vendor recommended protocol for the Applied Biosystems PrepFiler BTA extraction kit and an updated version of the same protocol, that substitutes Proteinase K with additional Dithiothreitol (DTT) (Thermo Fisher Scientific, 2012.). DNA quantitation was performed using pig-specific custom primer sets, with the QuantStudio 5 Real-Time PCR and PowerUp SYBR Green Master Mix (Thermo Fisher Scientific, 2022). Results showed that dry decomposition samples extracted using the updated protocol had a higher average quantity of DNA recovered than those extracted with the vendor recommended PrepFiler BTA protocol. At week three, all samples had lower DNA yields for both extraction methods. At week six and onward, DNA was recovered only from the dry decomposed samples extracted with the updated protocol. Wet decomposed samples and samples extracted with the PrepFiler BTA protocol yielded no DNA. The results of this study suggest that substituting Proteinase K with DTT during lysis yields significantly higher DNA quantities, improving recovery efforts from skeletal samples across increasing postmortem intervals. Analysts working with dry decomposed or otherwise challenging skeletal samples may consider implementing the updated extraction method into laboratory procedures.

Available for download on Wednesday, May 14, 2025

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