Development of a new 32-plex InDels panel for forensic purpose

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• Insertion/deletion polymorphisms (InDels) are increasingly recognized in forensic science due to their low mutation rates and small amplicon sizes.
• InDels offer advantages over traditional short tandem repeats (STRs) for forensic identification, particularly with challenging samples like degraded DNA.

Purpose of the Study:

• To develop and evaluate a multiplex assay for 32 insertion/deletion polymorphisms (InDels) plus amelogenin for forensic identification.
• To assess the performance of the 32-plex InDel assay in a southern Chinese Han population.

Main Methods:

• Selection of 32 InDels with a minimum allele frequency (MAF) ≥ 0.4 in the Chinese Han population, utilizing data from the 1000 Genomes Project and published literature.
• Establishment of a 32-plex InDel assay and its evaluation in a southern Chinese Han population from Hubei province.
• Assessment of assay sensitivity, effectiveness on degraded DNA, and comparison of allele frequencies with other populations.

Main Results:

• The 32-plex InDel assay demonstrated high polymorphism with an average observed heterozygosity (Hobs) of 0.4885.
• The assay achieved a combined power of discrimination (CPD) of 0.999999999999966 and a combined probability of paternity exclusion (CPE) of 0.9982.
• The assay proved highly sensitive, detecting DNA amounts as low as 31.25 pg, and was effective for degraded DNA samples.

Conclusions:

• The developed 32-plex InDel assay is a robust and sensitive tool for forensic identification.
• This assay provides a valuable alternative for challenging forensic cases involving degraded DNA, offering high discriminatory power.
• The allele frequency data generated contributes to the global understanding of InDel marker distribution in diverse populations.