Y-Short Tandem Repeat Multiplex Systems - Y-PLEX™ 6 and Y-PLEX™ 5.

Area of Science:

• Forensic genetics
• Molecular biology
• Human identification

Background:

• Y-Chromosome short tandem repeats (Y-STRs) are crucial for forensic casework, paternity testing, and male lineage research.
• Obtaining male DNA profiles from mixed samples is a significant challenge in forensics.
• Existing Y-STR genotyping systems require optimization for comprehensive analysis.

Purpose of the Study:

• To introduce and validate the Y-PLEX™ 6 and Y-PLEX™ 5 genotyping systems for human identification.
• To assess the sensitivity, specificity, and reliability of these Y-STR multiplex systems.
• To evaluate their utility in forensic casework and male lineage studies.

Main Methods:

• Simultaneous amplification of specific Y-STR loci using Y-PLEX™ 6 (DYS393, DYS19, DYS389II, DYS390, DYS391, DYS385) and Y-PLEX™ 5 (DYS389I, DYS389II, DYS439, DYS438, DYS392).
• Validation following FBI Director's Quality Assurance Standards, including sensitivity, specificity, and stutter analysis.
• Generation and sequencing of allelic ladders according to ISFG nomenclature.
• Testing on human and nonhuman primate DNA samples.

Main Results:

• Y-PLEX™ 6 and Y-PLEX™ 5 systems together cover 11 SWGDAM-recommended Y-STR loci.
• Minimum sensitivity was 0.2 ng (Y-PLEX™ 6) and 0.1 ng (Y-PLEX™ 5) of male DNA.
• Primers demonstrated specificity for human DNA and some higher primates, with mean stutter values ranging from 3.6% to 11.9%.
• The systems were successfully applied in forensic cases, with results admitted in U.S. Courts.

Conclusions:

• Y-PLEX™ 6 and Y-PLEX™ 5 are sensitive, reliable, and robust genotyping systems.
• These systems are highly suitable for forensic casework, paternity testing, and male lineage identification.
• Their comprehensive locus coverage and validated performance support their use in population database studies.