Detection of insertion/deletion polymorphisms from challenged samples using the Investigator DIPplex® kit

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• Forensic DNA analysis often faces challenges with degraded or limited biological samples.
• Short tandem repeat (STR) profiling can yield partial profiles from such samples.
• Insertion/deletion polymorphisms (InDels) offer an alternative or supplementary genetic marker.

Purpose of the Study:

• To evaluate the utility of the Investigator DIPplex® Kit for detecting bi-allelic InDels in challenging forensic samples.
• To establish an analytical threshold for reliable InDel detection.
• To assess the performance of InDels with various sample types and conditions.

Main Methods:

• Established an analytical threshold by assessing system noise.
• Generated InDel profiles from diverse samples: human body fluids (pristine and degraded), animal samples, washed bloodstains, lipsticks, ancient bone, toothbrushes, and dental floss.
• Tested direct amplification from substrates without pre-treatment.

Main Results:

• Successfully generated concordant InDel profiles from various human body fluids.
• Obtained InDel profiles from diverse and challenging sample types, including degraded and environmentally exposed materials.
• Demonstrated successful amplification directly from substrates.
• Confirmed species specificity with animal samples.

Conclusions:

• Insertion/deletion polymorphisms (InDels) are a robust tool for forensic analysis of challenged samples.
• InDels provide valuable genetic information when STR profiles are partial or absent.
• The Investigator DIPplex® Kit effectively detects InDels in a wide range of forensic contexts.