DNA Extraction From Post-mortem Human Teeth Samples For STR Profiling: Manual Vs Automated Techniques

Aim and Objective: This study aims to compare the efficiency of two DNA extraction methods- manual Qiagen and EZ1 automated platform – in obtaining high quality DNA from post-mortem human teeth samples for STR (Short Tandem Repeat) profiling. Introduction: Teeth are considered one of the most durable biological materials and serve as an excellent source of DNA particularly in challenging forensic scenarios like mass disasters and advanced decomposition. Choosing an adequate DNA extraction procedure has a considerable impact on the reliability of STR profiling in forensic identification. Materials and Methods: Two Post-mortem human teeth samples were randomly selected from the workflow of RFSL Chanakyapuri, New Delhi. Only human premolar teeth were included in the study to ensure uniformity in sample type for both extraction techniques. STR amplification was performed using GlobalFiler and PowerPlex 21 kits, and genotyping was analyzed via the 3500 Genetic Analyzer and GeneMapper 1.4 IDX software. Real-Time PCR (RT-PCR) results were utilized to measure DNA amplification efficiency. Results: The comparative analysis indicated variation in DNA yield, integrity and STR profiling success between the two methods. RT-PCR results were associated with both STR amplification and DNA quality. Conclusion: Manual DNA isolation methods were observed to yield better quality DNA as compared to automated protocols. This observation supports the use of manual extraction methods, especially in circumstances where DNA quantity is limited or the sample quality is compromised. A minimum threshold of DNA was essential for successful PCR amplification.