Date of Award

Summer 8-13-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department/Program

Forensic Science

Language

English

First Advisor or Mentor

Lissette Delgado-Cruzata

Second Reader

Marta Concheiro-Guisan

Third Advisor

Sarah Casado Zapico

Abstract

Ancestry-informative markers (AIMs) are genetic variants that exhibit significant frequency differences between populations, making them valuable tools for inferring biogeographical ancestry in forensic investigations. Insertion/deletion polymorphisms (INDELs) offer particular advantages for degraded forensic samples due to their short amplicon sizes and binary allelic nature. As forensic laboratories adopt newer instrumentation, validation of established assays becomes critical to ensure analytical continuity and reliability. This study evaluated the comparative performance of the SeqStudio™ Genetic Analyzer in detecting a 46 AIMs INDEL multiplex panel, previously established with the ABI 3130 Genetic Analyzer. Four commercial blood samples were analyzed using both platforms to assess detection capabilities and analytical performance under various forensic conditions including different extraction methods, controlled DNA degradation, and low-template DNA concentrations. The SeqStudio successfully detected 45 of 46 INDEL markers (97.8% call rate), with consistent dropout of one marker (MID-17) across all samples. The SeqStudio produced cleaner electropherograms with higher peak intensities, though sensitivity differences emerged at lower detection thresholds. Both QIAcube and Chelex extraction methods yielded equivalent allele detection performance, demonstrating assay robustness. Under degradation conditions, small amplicons (< 65 bp) showed superior performance with 67% partial amplification success, while larger fragments experienced complete dropout. The assay maintained consistent detection down to 0.05ng/µL input DNA concentrations, with significant dropout below 0.01 ng/µL. This validation demonstrates successful SeqStudio implementation for forensic applications.

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