Y-Chromosome STR system, Y-PLEX™ 12, for forensic casework: Development and validation

The Y-PLEX™ 12 system, developed for use in human identification, enables simultaneous amplification of eleven polymorphic short tandem repeat (STR) loci, namely DYS392, DYS390, DYS385 a/b, DYS393, DYS389I, DYS391, DYS389II, DYS19, DYS439 and DYS438, residing on the Y chromosome and Amelogenin. Amelogenin provides results for gender identification and serves as internal control for PCR. The validation studies were performed according to the DNA Advisory Board's (DAB) Quality Assurance Standards. The minimal sensitivity of the Y-PLEX™ 12 system was 0.1 ng of male DNA. The mean stutter values ranged between 3.76-15.72%. A full male profile was observed in mixture samples containing 0.5 ng of male DNA and up to 400 ng of female DNA. Amelogenin did not adversely affect the amplification of Y-STRs in mixture samples containing male and female DNA. The primers for the Y-STR loci present in Y-PLEX™ 12 are specific for human DNA and some higher primates. None of the primate samples tested provided a complete profile at all 11 Y-STR loci amplified with the Y-PLEX™ 12 system. Y-PLEX™ 12 is a sensitive, valid, reliable, and robust multiplex system for forensic analysis, and it can be used in human forensic and male lineage identification cases.