Optimization and Developmental Validation of 38-plex InDel Panel for Ancestry Inference

Area of Science:

• Forensic genetics
• Population genetics
• Molecular biology

Background:

• Established 38-plex Insertion/Deletion (InDel) system.
• Need for optimized performance and validation according to Scientific Working Group on DNA Analysis Method (SWGDAM) guidelines.
• Requirement for accurate ancestry inference across diverse populations.

Purpose of the Study:

• Optimize the 38-plex InDel system for enhanced performance.
• Validate the system's accuracy and reliability for forensic applications.
• Verify ancestry inference capabilities in various populations.

Main Methods:

• Optimized amplification conditions including primer balance, Mg2+ concentration, and PCR thermal cycling.
• Evaluated system performance based on allelic dropout, nonspecific amplification, and origin matching.
• Tested tolerance to common DNA inhibitors and direct amplification from saliva and blood on filter paper.

Main Results:

• Optimal DNA template dosage determined to be 0.125-2 ng.
• Demonstrated accurate InDel typing, good amplification equilibrium, and species specificity.
• Showed tolerance to inhibitors (hemoglobin, indigo, calcium ion, humic acid) and successful mixed DNA sample detection.

Conclusions:

• The 38-plex InDel system is accurate, reliable, and meets SWGDAM guidelines.
• The system accurately infers ancestry for African, European, East Asian, and Eurasian populations.
• The validated system is suitable for implementation in forensic practice.