A novel set of short microhaplotypes based on non-binary SNPs for forensic challenging samples

Area of Science:

• Forensic genetics
• Human population genetics

Background:

• Short tandem repeats (STRs) are standard forensic markers but struggle with degraded or mixed DNA samples due to large amplicons and stutter peaks.
• Novel genetic markers are needed to overcome limitations of current forensic tools for challenging samples.

Purpose of the Study:

• Develop and evaluate a novel panel of short microhaplotypes based on non-binary SNPs for forensic applications.
• Assess the discriminatory power and utility of this microhaplotype panel for personal identification, parentage testing, and ancestry inference.

Main Methods:

• Designed short microhaplotypes (<60 bases) using non-binary SNPs.
• Genotyped 100 individuals from northern Han groups.
• Evaluated population differentiation across 26 populations from the 1000 Genomes Project.

Main Results:

• The microhaplotype panel demonstrated high discrimination power, comparable to STR kits, with a combined random match probability (CMP) of 1.396 × 10^-22.
• Achieved high cumulative probabilities of exclusion for duos (0.999919) and trios (0.9999999987).
• Effectively distinguished between major continental populations, indicating utility for ancestry inference.

Conclusions:

• The developed microhaplotype panel offers a powerful tool for forensic personal identification and parentage testing.
• Its short amplicons, high discrimination, and lack of stutter artifacts make it ideal for analyzing degraded and unbalanced DNA mixtures.
• This panel shows significant potential for advancing forensic analysis and human population genetics research.