Performance evaluation of two multiplexes used in fluorescent short tandem repeat DNA analysis

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Background:

• Forensic laboratories rely on accurate short tandem repeat (STR) DNA profiling for criminal investigations.
• The U.S. national Combined DNA Indexing System (CODIS) utilizes 13 core STR loci for DNA identification.
• Validation of commercial DNA typing kits is crucial for ensuring reliable forensic analysis.

Purpose of the Study:

• To evaluate the performance of two commercial multiplex STR kits: AmpFlSTR Profiler Plus and AmpFlSTR COfiler.
• To validate the use of capillary electrophoresis (CE) with an ABI Prism 310 Genetic Analyzer for forensic DNA analysis.
• To assess key performance parameters including sensitivity, resolution, precision, and reliability with forensic samples.

Main Methods:

• Evaluation of AmpFlSTR Profiler Plus and COfiler kits for amplifying 13 core STR loci.
• Analysis of PCR products using capillary electrophoresis (CE) on an ABI Prism 310 Genetic Analyzer.
• On-site validation including sensitivity, resolution, binning, peak height ratios, mixtures, stutter, and environmental sample testing.

Main Results:

• Both multiplex kits demonstrated robust amplification and specificity to human DNA.
• Capillary electrophoresis consistently resolved fragments differing by one base, with acceptable binning by Genotyper software.
• Accurate typing results were achieved for non-probative, simulated, and environmentally challenged forensic samples.

Conclusions:

• AmpFlSTR Profiler Plus and COfiler kits are reliable for analyzing forensic DNA samples using CE.
• The validated methods support consistent and accurate STR profiling in routine forensic casework.
• These findings affirm the suitability of the evaluated kits and CE technology for forensic DNA databases like CODIS.