Defense Date
2024
Document Type
Directed Research Project
First Advisor
Dr. Tal Simmons
Second Advisor
Dr. Baneshwar Singh
Third Advisor
Dr. Jenise Swall
Abstract
In April 1994, the discovery of the East Marshall Street Well (EMSW) at Virginia Commonwealth University revealed 19th-century skeletal remains and artifacts. These remains, commingled and degraded over time, provide crucial historical insights into past grave-robbing practices for medical education. The aim of this research was to employ forensic DNA profiling techniques, specifically using Insertion Null Alleles (INNULs) and precisely adjusted analytical thresholds, to identify and respectfully memorialize individuals from these commingled remains. The study analyzed 536 bone samples, including four reference samples, using the InnoQuant® HY kit and the QuantStudio™️ 6 Real-Time PCR system, with the InnoTyper® 21 Kit for genotyping INNULs in degraded DNA.This process yielded complete DNA profiles for 31 samples, partial profiles for 112 samples, and no profiles for 110 samples. From the matching process, 19 individuals were successfully identified. The analysis faced limitations resulting in the exclusion of four groups from the final count due to insufficient DNA or contamination. Sensitivity analysis demonstrated that the kits could detect DNA input as low as 0.05 ng, with optimal detection at 0.25 ng. The peak height ratios highlighted this sensitivity, dropping from 3,195 RFU at 1 ng to 197 RFU at 0.05 ng. Adjusting analytical thresholds was crucial for identifying additional alleles in low-template DNA samples, which significantly affected the likelihood ratios (LRs). In certain cases, LRs increased from 1,059 to 2,503, and in one instance, from 34.31 million to 441.5 million, highlighting an improvement of 1,187%. These findings underscore the importance of precise analytical thresholds for accurate allele identification and LR calculations, which are essential for the reliable association of bones and accurate historical reconstruction of the EMSW remains. The study advances forensic DNA analysis by offering effective techniques for analyzing degraded or commingled remains and emphasizes that INNUL markers and analytical thresholds are invaluable tools in forensic applications. They enhance the accurate and respectful identification of individuals in historical forensic investigations.
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
4-25-2024