| Y-STR analysis can be useful when autosomal DNA typing fails. Particularly true in sexual assault cases, problems can arise with autosomal analysis, when there is a high female DNA/low male DNA ratio, when no sperm cells are present (e.g. azoospermic semen, blood, saliva, fingernail scrapings), or when there is more than one male assailant. There are several Y-STR amplification systems that have been generated, some of which are commercially available.; The Reliagene Y-STR systems Y-PLEX(TM) 5 and Y-PLEX(TM) 6 enable simultaneous amplification of eleven loci on the Y-chromosome. The overall goal of this project was to validate these Y-STR systems for analysis on an ABI PrismRTM 3100 genetic analyzer at the Michigan State Police Forensics Science Division. This was accomplished by conducting studies to determine the minimum sensitivity of each Y-PLEX(TM) system, the precision of allele sizing using both an ABI PrismRTM 310 and 3100 genetic analyzer, and the concordance between the two instruments. Finally, an interethnic study was conducted by analyzing approximately 100 samples from three ethnic groups, Caucasian, African American, and Hispanic. The minimum sensitivity for the Y-PLEX(TM) 5 and Y-PLEX(TM) 6 systems were 0.3125ng and 1.25ng respectively. In the interethnic study an increase in the haplotype diversity and the number of unique haplotypes was observed when comparing the haplotypes containing the 11 loci of Y-PLEX(TM) 5 and 6 compared to the haplotypes containing either the Y-PLEX(TM) 5 or 6 loci alone. |
