Validation of Automated PrepFiler Versus Organic Manual Extraction

The isolation of DNA from forensic samples is the most imperative, yet challenging, step in DNA profiling. Biological samples at crime scenes can be found in a variety of conditions which can expose the DNA to inhibitors and nucleases; all which impede STR Profiling. We are investigating the yield and quality of DNA extracted from samples using the new PrepFiler Extraction kit and Tecan Robotic Workstation in comparison to Organic Extraction with Microcon YM-100 concentration. The PrepFiler kit uses magnetic particles and a multi-component surface chemistry to enable extremely efficient DNA binding and recovery. We are also introducing the use of the Lysep Column which will simplify the separation of a substrate from the lysate thus minimizing manipulation of a sample. We hypothesize that the PrepFiler Extraction kit will improve the yield and consistency of DNA recovery in comparison to Organic Extraction. This validation includes testing blood and saliva samples in a variety of concentrations to address sensitivity, reproducibility, and accuracy. Biological material on soil, indigo-dyed jeans, handguns, and chewing gum will be extracted and evaluated in a substrate study. The performance of both extractions will be assayed using qPCR to compare the amount of DNA isolated and STR amplification to detect any inhibitor or nuclease contamination. If the quality and quantity of DNA improves with the use of the PrepFiler chemistry, the laboratory will modify its workflow to implement this new technology. This will allow for higher throughput, reduce PCR inhibitors, and eliminate the use of toxic Phenol:Chloroform:Isoamyl Alcohol.