Optimizing cell yield and fraction separation from mixed sample swabs using temperature controlled differential extraction methods
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Citation
Abstract
The optimization of DNA extraction methods from mixed sample swabs is critical in forensic science, particularly when dealing with complex samples containing contributions from multiple individuals. This thesis investigates the use of Temperature-Controlled Differential Extraction (TCDE) methods to enhance cell yield and improve the separation of DNA fractions from mixed samples, such as vaginal, semen, and buccal swabs. The primary objective of this research was to refine TCDE protocols to achieve higher efficiency in isolating target DNA fractions (e.g., epithelial and sperm fractions) while minimizing carry-over between contributors. A series of experiments were conducted using a variety of sample types, including single-source and mixed samples, with variations in reagent preparation, enzyme treatments, and incubation conditions. Challenges were noted in the separation of DNA from mixed vaginal and semen samples, particularly in the incomplete recovery of female DNA in some mixed samples, such as mixed sample XY-J, where missing alleles were identified in the epithelial and material fractions. The findings highlight the effectiveness of the optimized TCDE protocol in extracting high-quality DNA profiles from both single-source and mixed samples, though further refinement may be necessary to enhance consistency and address the challenges of profiling mixed contributors. This research contributes to the ongoing efforts to improve forensic DNA analysis, with potential applications in criminal justice and human identification.Keywords: Differential extraction, mixed samples, forensic DNA analysis, temperature-controlled differential extraction (TCDE), DNA recovery, epithelial fraction, sperm fraction, forensic science
Description
2025
License
Attribution 4.0 International