Development and validation of a multiplexed Y-chromosome STR genotyping system, Y-PLEX 6, for forensic casework

Area of Science:

• Forensic Genetics
• Molecular Biology
• Human Identification

Background:

• Short tandem repeat (STR) analysis is crucial for human identification.
• Y-chromosome STRs (Y-STRs) are valuable for male lineage tracing and complex mixture analysis.
• Existing Y-STR kits may have limitations in sensitivity or specificity.

Purpose of the Study:

• To develop and validate a novel multiplex polymerase chain reaction (PCR) amplification kit, Y-PLEX 6, for human identification.
• To assess the sensitivity, specificity, and reliability of the Y-PLEX 6 kit.
• To determine Y-STR allele and haplotype frequencies in different populations.

Main Methods:

• Development of a multiplex PCR kit (Y-PLEX 6) amplifying six Y-STR loci (DYS393, DYS19, DYS389II, DYS390, DYS391, DYS385).
• Evaluation of DNA template requirements, down to 0.2 ng.
• Testing specificity using male:female DNA mixtures and animal DNA.
• Analysis of Y-STR allele and haplotype frequencies in three populations.

Main Results:

• The Y-PLEX 6 kit successfully amplified six Y-STR loci simultaneously.
• High sensitivity demonstrated, with analysis possible from as little as 0.2 ng of DNA.
• Excellent specificity shown, enabling male DNA detection in 1:125 male:female mixtures and confirming human specificity.
• Robust and reliable results obtained across tested populations.

Conclusions:

• The Y-PLEX 6 kit is a sensitive, specific, and reliable tool for human identification.
• It is suitable for forensic casework and male lineage identification, including challenging samples.
• Population data generated provides valuable reference for interpretation of results.