Experience with the PCR-based HLA-DQ alpha DNA typing system in routine forensic casework

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Background:

• Human Leukocyte Antigen (HLA) typing is crucial in forensic investigations.
• The polymerase chain reaction (PCR) technique enhances DNA analysis sensitivity.
• HLA-DQ alpha locus offers a specific genetic marker for identification.

Purpose of the Study:

• To evaluate the reliability, discrimination efficiency, and informative value of HLA-DQ alpha typing in routine forensic casework.
• To assess the utility of PCR-based HLA-DQ alpha typing across diverse forensic sample types.
• To determine the practical application of HLA-DQ alpha typing in suspect inclusion/exclusion.

Main Methods:

• Analysis of 42 routine forensic cases involving 125 individual stain and tissue samples.
• Application of polymerase chain reaction (PCR) for HLA-DQ alpha typing.
• Examination of various sample types including blood, semen, mixed fluids, hair, cigarette butts, and tissue.

Main Results:

• PCR amplification was successful in 70% of the analyzed samples.
• HLA-DQ alpha typing was consistently successful for mixed body fluid samples.
• Only approximately 42% of successfully typed samples provided relevant information for suspect inclusion or exclusion.

Conclusions:

• HLA-DQ alpha typing using PCR demonstrates variable utility in forensic casework.
• The limited number of alleles and sample origin (victim vs. perpetrator) can reduce the informative value.
• Further development or alternative genetic markers may be needed to improve discriminatory power in forensic investigations.