Performance of the PowerPlexY23® kit on trace samples in forensic genetic casework

Abstract

Y-chromosomal short tandem repeats (Y-STRs) can be analysed with the AmpFlSTR®Yfiler® kit (Yfiler, Life Technologies (LT)) from trace samples in forensic case-work. However, the results are not reliable when the ratio of female:male DNA is high. The aim of this study was to investigate the performance of the PowerPlex®Y23 kit (PPY23, Promega) on trace samples from crime scenes. A total of 100–200pg male DNA was analysed with the PPY23 kit from 45 trace samples. Amplification of Y-STRs with the PPY23 kit was successful for 34 (76%) of the trace samples. Reproducible artefact peaks in the reading area (80–450 base pairs) were found in up to 29% of the trace samples typed with the PPY23 kit. Significantly higher female:male DNA ratios were observed in profiles with artefact peaks compared to those of profiles with no artefact peak. It was concluded that the quality of Y-STR analyses of trace samples would not be improved by replacing the Yfiler kit with the PPY23 kit in our laboratory.