QIAcube System in Touch DNA Extraction

Objective To explore the applicability of QIAcube Forensics Casework DNA extraction system into extracting touch DNA and evaluate the effect. Methods 30 samples were transferred from forensic biological evidence using tape-lifting technique, 30 samples transferred by yarns and 30 samples transferred using double swab technique. All these 90 samples were extracted by QIAcube, EZ1 and Si O2 extraction systems respectively, then quantified and detected by STR typing. Results Up to 44.4% touch DNA were successfully detected by QIAcube extraction system, with successful rate of 56.7% in tape-lifting group, 46.7% in yarns group and 30.0% in double swab group. Both forensic biological evidence of tape lifting group and yarns group got good STR typing results using QIAcube extraction system,and the DNA concentrations were higher than that of swab group. QIAcube and Si O2 extraction system got good STR typing, especially at the large fragment loci,and the concentrations of extracted DNA were higher than that of EZ1 extraction system. Up to 44.4% touch DNA were detected by QIAcube extraction system, while the Si O2 extraction system was 43.2% and the EZ1 extraction system was 26.9%. There was no statistical difference in DNA concentration between QIAcube and Si O2 system, which were both obviously higher than that of EZ1 extraction system. Conclusions QIAcube extraction system is an effective method to extract DNA from forensic biological evidence, applicable into forensic practice.