Coding region SNP analysis to enhance dog mtDNA discrimination power in forensic casework

Area of Science:

• Veterinary Genetics
• Forensic Science
• Molecular Biology

Background:

• The dog mitochondrial DNA (mtDNA) control region exhibits low discrimination power due to high frequencies of specific haplotypes.
• This limitation reduces the evidential value of mtDNA matches in forensic investigations involving dogs.

Purpose of the Study:

• To develop and validate novel assays for single nucleotide polymorphism (SNP) sites within the dog mitochondrial genome.
• To enhance the discriminatory capacity of canine mtDNA analysis for forensic applications.

Main Methods:

• Mitochondrial genome sequencing of 214 Belgian dogs identified 26 polymorphic coding region sites.
• Development of three SNP assays to target these informative sites.
• Application of assays to newly sampled dogs and integration with existing data for population-level analysis.

Main Results:

• The 26 coding region sites successfully resolved dogs previously grouped by common control region haplotypes.
• Application of the three SNP assays confirmed their efficacy in increasing dog mtDNA discrimination.
• Analysis of 346 dogs revealed 25 distinct clusters using the 26 sites, with lower population frequency estimates compared to control region haplotypes.

Conclusions:

• The developed SNP assays effectively increase the discrimination power of dog mtDNA analysis.
• Utilizing these assays alongside control region sequencing significantly enhances the exclusion probability in forensic casework, improving from 92.9% to 97.0%.