Practical forensic use of kinship determination using high-density SNP profiling based on a microarray platform,...

Area of Science:

• Forensic genetics
• Human genetics
• Molecular biology

Background:

• Traditional short tandem repeat (STR) profiling has limitations in kinship determination, especially for distant relationships.
• Genetic genealogy utilizing genome-wide single nucleotide polymorphisms (SNPs) is an emerging powerful tool for kinship analysis.
• Low-quantity DNA samples pose challenges for accurate genotype determination in forensic applications.

Purpose of the Study:

• To evaluate the tolerance and viability of kinship discrimination using high-density SNP profiles with low-quantity forensic DNA.
• To investigate the impact of genotyping errors in low-quality SNP profiles on kinship analysis.
• To develop a novel method for robust SNP selection to improve kinship discrimination accuracy.

Main Methods:

• Utilized the Affymetrix Genome-Wide Human SNP Array 6.0 for SNP genotyping.
• Evaluated the influence of low-quantity DNA on SNP genotype determination and data quality.
• Developed and applied a novel method for selecting robust SNPs resistant to genotyping errors.
• Employed KING software for kinship discrimination analysis.

Main Results:

• Low-quantity DNA samples resulted in SNP profiles with low data quality and increased genotyping errors (e.g., homozygote to heterozygote changes).
• Genotyping errors led to misclassification of kinship, incorrectly identifying unrelated pairs as relatives.
• The novel robust SNP selection method significantly improved kinship discrimination accuracy, achieving results comparable to high-quality SNP profiles.
• High-density SNP profiling demonstrated advantages over STR profiling for kinship analysis, particularly for distant biological relationships.

Conclusions:

• A novel method for selecting robust SNPs effectively mitigates genotyping errors in low-quality DNA profiles, enabling accurate kinship discrimination.
• High-density SNP profiling is a viable and advantageous tool for forensic kinship analysis, especially in cases involving distant relatives.
• Further research with larger sample sizes is warranted, but this approach shows significant promise for practical forensic applications.