The study for the DNA case work sample purification by the automated DNA extraction system with magnetic beads / 中国法医学杂志

ABSTRACT

Objective To evaluate the forensic application of TE-MAGS technology based on magnetic beads kit on TECAN pipetting platform and establish the automated DNA extraction system of case work samples. Methods Sensitivity test: 10 different DNA samples from 0.1ng to 1ng were prepared with a commercial standard DNA 9947A diluted into 200μL TES. DNA samples were purified by the TE-MAGS technology automatically on the TECAN pipetting platform and then typed using the IdentifilerTM Kit and get the profile of STR with the software GeneMapper ID-X; the power of purification was tested with a trail that purified 1ng DNA mixed with humus acid and hemachrome. Comparative test: 304 casework samples were divided into two purified by TE-MAGS technology and silicon beads respectively to compare the power of purification and the possibility of forensic utility. Results Sensitivity test: 0.3ng and more imported DNA can obtain a good quality of DNA profile compared to the lower imported DNA with dropout of STR peaks (0.1ng and 0.2ng). The power of purification of the TE-MAGS technology was not affected by humus acid and hemachrome. The comparison result between automatic TE-MAGS technology and manual silicon beads extraction methods from 304 casework samples showed that the former's success rate(50%) was higher than the latter(40.8%). Conclusion The established DNA purification method of TE-MAGS technology automatic DNA extraction system in this study was obviously advantaging at the aspect of success rate, stability, and uniformity and suited to application in the forensic utility future.