Development of a new 26plex Y-STRs typing system for forensic application

Area of Science:

• Forensic Genetics
• Human Identification
• Molecular Biology

Background:

• Y-chromosome Short Tandem Repeats (Y-STRs) are crucial for male lineage tracing in forensic genetics.
• Existing Y-STR multiplex systems vary in the number of loci and discriminatory power.
• The need for highly discriminating and rapid Y-STR typing systems for forensic applications is ongoing.

Purpose of the Study:

• To establish and validate a novel 26plex Y-STR typing system.
• To assess the sensitivity, specificity, and robustness of the new system.
• To evaluate its forensic efficacy, including mixture analysis and speed.

Main Methods:

• Development of a 26plex Y-STR typing system using 5-dye fluorescence labeling, incorporating 17 YHRD standard loci and 9 novel Y-STRs.
• Developmental validation including reproducibility, accuracy, sensitivity, and specificity testing.
• Forensic evaluation using 517 unrelated males to determine haplotype diversity and discrimination capacity.

Main Results:

• The 26plex Y-STR system demonstrated high sensitivity, yielding full profiles from 125pg of male DNA, even with excess female DNA.
• The system showed excellent performance in mixture studies, detecting minor alleles at high percentages.
• PCR amplification was completed in 1 hour, enabling fast detection.
• High haplotype diversity (HD) of 0.9999925 and discrimination capacity (DC) of 0.9980658 were achieved.

Conclusions:

• The developed 26plex Y-STR typing system is reproducible, accurate, sensitive, robust, and suitable for forensic applications.
• Its high discriminatory power and speed make it a valuable tool for male DNA profiling and identification.
• The system effectively resolves male DNA mixtures and is efficient for rapid forensic analysis.