DNA microarray for forensic intelligence purposes: High-density SNP profiles obtained directly from casework-like...

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• Single nucleotide polymorphism (SNP) analysis is crucial for forensic intelligence, aiding in suspect identification and locating missing persons.
• DNA microarray assays show promise for forensic applications, including genetic genealogy.

Purpose of the Study:

• To evaluate DNA microarray assay performance on saliva samples collected using a double swab technique from a glass surface, simulating crime scene conditions.
• To assess the reliability of genotype data generated with and without a DNA purification step.

Main Methods:

• Eighteen saliva samples from one individual were analyzed using the Infinium® Global Screening Array-24 v1.0 (~642,824 SNP markers).
• Two protocols were tested: with and without DNA purification.
• Genotype data quality was assessed using Call Rate and GenCall Scores, compared against a Consensus Genotype.

Main Results:

• The Call Rate parameter is sufficient for estimating genotype accuracy in SNP assays.
• Reliable genotypes with >90% confidence were achieved at Call Rates above 69.41%, irrespective of the protocol.
• High-density SNP profiles with >90% confidence were generated from simulated crime scene samples.

Conclusions:

• DNA microarray assays can produce reliable, high-density SNP genetic profiles from challenging forensic samples.
• Future protocol optimizations, including potentially eliminating the DNA purification step, could enhance microarray utility for crime analysis.
• DNA microarrays offer a valuable tool for forensic intelligence, supporting criminal investigations.