Background

Y-STR typing is an indispensable tool in forensic genetics for discriminating male components in complex mixtures and tracing paternal lineages. However, environmental degradation and low template DNA often hinder the performance of standard Y-STR kits. To address these challenges, we developed a highly multiplexed mini-Y-STR system designed to maximize recovery from compromised biological evidence.

Methods and Design

This system employs a strategic short-amplicon and dual-panel (Panel A and Panel B) design, enabling the simultaneous amplification of 43 mini-Y-STR loci within 55 minutes. Key design features include:

1. Amplicon Size: All 43 amplicons are optimized to be under 300 bp to enhance performance on fragmented DNA.
2. Panel Composition: Panel A targets 20 core Y-STR loci, while Panel B includes 19 additional commonly used Y-STR loci.
3. Internal Controls: DYS437 and three Y-Indels are shared between both panels to serve as internal controls, ensuring cross-panel amplification consistency and reliability.

Results

Validation studies demonstrate exceptional sensitivity and robustness. The system consistently yields complete Y-chromosomal profiles from as little as 50 pg of male genomic DNA. In mixture analysis, full profiles of the minor contributor are recoverable at a 1:8 male–male ratio, and male DNA can be fully detected even in a 1:48,000 male–female ratio. Furthermore, the system exhibits high tolerance to common PCR inhibitors and maintains stable performance under variations in annealing temperatures (±1.5°C) and reagent concentrations (±20%).

Conclusion

Through the synergistic design of minimized amplicons and dual-panel multiplexing, this 43-loci mini-Y-STR system provides an accurate and reliable technical platform for male genetic identification. It is specifically engineered to handle the most challenging forensic cases involving degraded, low-template, and highly unbalanced mixed samples.

Keywords

Forensic Genetics; Mini Y-STR; Male Identification; DNA Degradation; Mixture Analysis; High Sensitivity

Authors

• Sheng Li (Nuhigh biotechnologies Co Ltd., China)
• Dongke Fu (Nuhigh biotechnologies Co Ltd., China)
• Wanli Bi (Nuhigh biotechnologies Co Ltd., United States of America)