Development of a multiplex panel with 31 multi-allelic InDels for forensic DNA typing

Area of Science:

• Forensic Genetics
• Human Genomics
• Molecular Biology

Background:

• Insertion/Deletion (InDel) markers are common in human genomes, but diallelic InDels have limited forensic application due to low polymorphic information content.
• Existing InDel panels require improvement for robust forensic identification, particularly for complex or degraded samples.

Purpose of the Study:

• To develop and optimize a novel multiplex amplification system (FA-HID32plex) utilizing multi-allelic InDel markers for enhanced forensic applications.
• To evaluate the performance of the FA-HID32plex panel in terms of sensitivity, specificity, robustness, and discriminatory power.

Main Methods:

• Selection of multi-allelic InDels outside low complexity regions in East Asian populations.
• Construction and optimization of a multiplex amplification system including 31 multi-allelic InDels and the Amelogenin marker (FA-HID32plex).
• Assessment of sensitivity, species specificity, inhibitor tolerance, mixture resolution, and degraded sample detection.

Main Results:

• The FA-HID32plex system demonstrated high sensitivity, specificity, and robustness, performing well with trace and degraded samples.
• The combined power of discrimination (CPD) for the 31 multi-allelic InDel markers reached 0.999 999 999 999 999 999 85.
• The cumulative probability of exclusion (CPE) was 0.999 920 in a Chinese Han population, indicating significant discriminatory capability.

Conclusions:

• The FA-HID32plex panel offers a powerful tool for individual identification and paternity testing, especially when dealing with challenging forensic samples.
• This multi-allelic InDel system provides reliable supplementary or stand-alone genetic information, improving upon limitations of previous diallelic InDel markers.