Automated Forensic DNA Purification Optimized for FTA Card Punches and Identifier STR-based PCR Analysis

摘要

Forensic labs globally face the same problem-a growing need to process a greater number and wider variety of samples for DNA analysis. The same forensic lab can be tasked all at once with processing mixed casework samples from crime scenes, convicted offender samples for database entry, and tissue from tsunami victims for identification. Besides flexibility in the robotic system chosen for forensic automation, there is a need, for each sample type, to develop new methodology that is not only faster but also more reliable than past procedures. FTA is a chemical treatment of paper, unique to whatman Bioscience, and is used for the stabilization and storage of biological samples. Here, we describe optimization of the Whatman FTA Purification Kit protocol for use with the AmpFISTR Identifier PCR Amplification Kit. The conditions giving the best quality Identifier results were used to automate a simple rapid method that processed forensic samples applied to FTA-treated paper punches in a 96-well plate in ～30 min. We describe an automated DNA purification procedure using 1.25 mm bloodstained FTA punches that is easily scalable and can be used with both convicted offender and reference casework bloodstained and buccal-swiped FTA samples. It works equally well with the Profiler Plus PCR Amplification Kit. Fully automated drying and polymerase chain reaction (PCR) amplification setup of short tandem repeat (STR) loci can be added to expand the walk-away process.