Forensic performance of two insertion-deletion marker assays.

Area of Science:

• Forensic genetics
• Molecular biology
• Human identification

Background:

• Analyzing degraded DNA is a significant challenge in forensic science.
• Short, biallelic insertion-deletion length polymorphisms (InDels) are emerging as promising markers for degraded DNA analysis.
• InDels offer advantages similar to single-nucleotide polymorphisms (SNPs), including short amplicon sizes and high multiplexing capabilities.

Purpose of the Study:

• To evaluate the forensic utility of InDels for human identification.
• To characterize population variation for InDel markers in diverse US populations.
• To assess the performance of InDel assays with degraded and mixed DNA samples.

Main Methods:

• Utilized two highly multiplexed InDel assays: a 30-plex (Qiagen DIPplex) and a 38-plex panel.
• Generated allele frequencies for 68 InDel markers across African American, Caucasian, East Asian, and Hispanic populations.
• Assessed assay performance using artificially degraded DNA and mixed-source samples.

Main Results:

• InDel genotyping proved effective for human identification, adding informative loci to forensic marker sets.
• Population variation data were generated for 68 InDel markers.
• Characterized profile artifacts and performance issues relevant to routine forensic use.

Conclusions:

• InDel genotyping represents a valuable new approach for forensic DNA analysis, particularly for degraded samples.
• The characterized InDel markers enhance the existing forensic genetic toolkit.
• These findings support the routine implementation of InDel assays in forensic casework.