A casework study comparing success rates and expectations of detecting male DNA using two different Y-STR multiplexes on vaginal swabs in sexual assault investigations where no semen has been detected.

Sexual assault cases where there is an allegation of digital or penile penetration but no semen is detected on the vaginal swabs have historically been difficult to investigate due to the high background levels of female DNA present. Previous studies have shown the value of Y-STR analysis in such cases. This study aims to provide: 17% of the cases in this study generated Y-STR profiles suitable for subjective or statistical evaluation following analysis with Yfiler compared with 34% of the cases analysed with Powerplex Y23, demonstrating the value of using more recently developed Y-STR multiplexes compared with older kits.