Forensic identity SNPs: Characterisation of flanking region variation using massively parallel sequencing

Area of Science:

• Forensic genetics
• Population genetics
• Genomics

Background:

• Single nucleotide polymorphisms (SNPs) are valuable for forensic identity and kinship analysis.
• Massively parallel sequencing (MPS) facilitates large-scale SNP typing and provides sequence data for flanking regions.
• Traditional SNP analysis often overlooks variations in flanking regions.

Purpose of the Study:

• To evaluate the impact of including flanking region variation on the discriminatory power of 94 identity-informative SNPs.
• To present allele frequencies for these SNPs across diverse UK populations.
• To assess the performance of these SNPs within the ForenSeq DNA Signature Prep Kit.

Main Methods:

• Genotyping of 977 samples from five UK populations using the ForenSeq DNA Signature Prep Kit.
• Analysis of 94 identity-informative SNPs and their flanking regions.
• Calculation of allele frequencies and combined match probabilities with and without flanking region data.

Main Results:

• Identification of 158 additional alleles by examining flanking region variation.
• Inclusion of flanking region data reduced average combined match probability 2175-fold across populations.
• Enhanced discrimination increased heterozygosity at some loci, surpassing certain forensic STR loci.

Conclusions:

• Incorporating flanking region variation in SNP analysis significantly boosts forensic discriminatory power.
• This enhanced approach improves the effectiveness of SNP markers for identity and kinship applications.
• The ForenSeq DNA Signature Prep Kit effectively captures flanking region variation for advanced forensic analysis.