Optimizing amplification threshold of low template DNA

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Background:

• Low template DNA (LTDNA) samples present significant processing challenges in forensic laboratories.
• Efficiently analyzing LTDNA is crucial for maximizing the information obtained from limited biological evidence.

Purpose of the Study:

• To optimize amplification criteria for low-quantity forensic DNA samples.
• To establish thresholds for DNA concentration and degradation index to predict amplification success.

Main Methods:

• Analysis of 155 real forensic case samples with DNA concentrations ranging from 5 to 14.3 pg/μL.
• Utilized the PowerPlex® ESI 16 Fast System for DNA amplification.
• Categorized samples based on DNA concentration, degradation index, and predicted success rate.

Main Results:

• 27% of analyzed low template DNA samples yielded informative DNA profiles.
• Success rates were higher for samples with DNA concentrations >10 pg/μL and degradation index <3.
• Established empirical thresholds for sample selection.

Conclusions:

• Implementing optimized thresholds can reduce laboratory workload by 32%.
• This approach retains 83% of informative profiles from low template DNA samples.
• Balances comprehensive evidence processing with resource management in forensic settings.