Evaluation of the Y-screening and EZ1 differential extraction utilization by a crime laboratory
OA Version
Citation
Abstract
Due to the frequent occurrence of sexual assaults, crime laboratories often face resource and personnel shortages when attempting to process the large numbers of sexual assault cases submitted to the Laboratory in a timely manner. As a result, laboratories may accumulate a backlog of Sexual Assault Kits (SAEKs). To address this issue, some crime laboratories have adopted Y-screening as an alternative to traditional serological tests for semen detection. This study examines the effectiveness of Y-screening and the EZ1 differential extraction method in the analysis of SAEKs and attempts to determine whether Y-screening can accurately predict the presence and amount of male and female deoxyribonucleic acid (DNA) in relevant samples. The information can be used by the laboratory to evaluate the forensic process and is designed to alleviate SAEK backlogs. By analyzing real casework quantification values and looking at simulated samples, the precision of Y-screening in estimating DNA concentrations and the ability of the EZ1 system to separate male from female DNA were evaluated. The research identified significant variability in the distribution of DNA across samples and noted that there is DNA loss during the EZ1 extraction process, in part because a portion of male DNA remains on the swab post-extraction. While Y-screening effectively detected male DNA, relying on its quantitative polymerase chain reaction (qPCR) results to decide how much sample to use for short tandem repeat (STR) analysis was sometimes inaccurate. These findings underscore the necessity for further understanding and refinement of forensic protocols and technologies to enhance the handling of sexual assault evidence.
Description
2024
License
Attribution 4.0 International