Performance of the SNPforID 52 SNP-plex assay in paternity testing

Area of Science:

• Forensic Genetics
• Human Identification
• Molecular Biology

Background:

• Traditional genetic markers like Short Tandem Repeats (STRs) and Variable Number Tandem Repeats (VNTRs) are widely used in human identification and relationship testing.
• These markers can be prone to mutations, potentially complicating casework.
• Single Nucleotide Polymorphisms (SNPs) offer an alternative with potentially lower mutation rates.

Purpose of the Study:

• To evaluate the performance of a 52-SNP multiplex assay for human identification and relationship testing.
• To compare the efficacy of SNP markers against traditional STR and VNTR markers in paternity index calculations.
• To assess the mutation rates of SNP loci compared to tandem repeat loci.

Main Methods:

• A multiplex assay using 52 autosomal SNPs was tested on 124 mother-child-father trios.
• Paternity Indices (PIs) were calculated for SNP, STR, and VNTR data.
• Extensive comparisons were made between mother-child duos and unrelated men using SNP profiles.
• Mutation rates were analyzed for both SNP and tandem repeat loci.

Main Results:

• The 52-SNP assay yielded typical PIs of 10^5-10^6 for trios and 10^3-10^4 for duos.
• Out of 83,096 comparisons, only two unrelated men showed a perfect match to a mother-child duo, with true fathers having higher PIs.
• No mutations were detected in the SNP loci, while six mutations were found in tandem repeats.
• STR and VNTR markers provided 5-50 times higher PIs than the 52-SNP assay.

Conclusions:

• The 52-SNP multiplex assay is a valuable and reliable tool for relationship testing, offering an alternative to current methods.
• The low mutation rate of SNP markers enhances their utility in paternity and immigration casework.
• SNPs provide a robust genetic profile for human identification, particularly in scenarios where marker stability is crucial.