Elimination of contaminating amplified short tandem repeat products by autoclaving and ultraviolet irradiation

DNA contamination can result in false interpretation of short tandem repeat (STR) DNA typing. Proper decontamination is particularly required in forensic DNA laboratories where probative value of the evidence may be affected. The aim of this study was to establish an effective DNA decontamination procedure for amplified STR products focusing on laboratory-related contamination. We verified the effectiveness of thermally and temporally extended autoclaving and ultraviolet irradiation for the elimination of contaminating amplified STR products. STR amplification products were prepared using a control genomic DNA template and generated using the AmpF？STR？ Identifiler？ Plus and Yfiler？ polymerase chain reaction amplification kits. In this study, the contaminants were dried before decontamination treatment, which resembles actual contamination situations. One microlitre of amplified STR products was eliminated by a combination of autoclaving (128°C, 420 min) and UV irradiation (60 J/cm2). Our results reveal that the combination treatment represents an effective DNA decontamination procedure and a practicable method in standard level laboratories. Finally, we propose a comprehensive approach for forensic DNA laboratories to implement to minimise contamination issues and guarantee provision of authentic results