Adventitious match probability for autosomal profiles when primer binding site mutation is possible.

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• DNA profiling systems utilize specific primers to amplify and analyze genetic loci.
• Primer binding site mutations (PBSMs) can occur, preventing allele visualization at a specific locus.
• PBSMs can alter a DNA profile, potentially leading to misinterpretations, especially in heterozygous individuals.

Purpose of the Study:

• To investigate the impact of primer binding site mutations (PBSMs) on adventitious match probabilities in DNA databases.
• To assess the risk of false matches between DNA profiles from different individuals due to PBSMs.
• To evaluate the theoretical and simulated effects of PBSMs on DNA database search outcomes.

Main Methods:

• Theoretical analysis of allele drop-out caused by PBSMs.
• Computer simulations to model DNA profile comparisons with and without PBSMs.
• Examination of adventitious match probabilities under different mutation scenarios.

Main Results:

• Primer binding site mutations can cause a heterozygous profile to appear homozygous.
• The occurrence of PBSMs was shown to slightly reduce the probability of an adventitious match.
• Simulations confirmed the theoretical decrease in adventitious match probability due to PBSMs.

Conclusions:

• PBSMs represent a potential artifact in DNA profiling that can alter profile interpretation.
• While PBSMs can cause profile discrepancies, they slightly decrease the likelihood of false positives in DNA database searches.
• Understanding PBSM effects is crucial for accurate DNA profile analysis and database integrity.