A preliminary mitochondrial DNA SNP genotyping assay for inferring genealogy

The description of phenotypic traits as a result of eyewitness accounts at crime scenes is a standard police practice. Traditional facial composites have been enhanced more recently by computer-aided photofitting techniques. The ‘silent witness’ of DNA evidence also has the potential to provide ‘molecular photofits’. Ancestry as a phenotypic trait is particularly amenable to molecular photofitting as the establishment of human origins through mitochondrial DNA (mtDNA) and Y chromosome haplotyping has been the subject of much recent interest. In this study, a multiplex mtDNA single nucleotide polymorphism (SNP) genotyping assay was devised to assign maternally inherited mtDNA to one of 15 haplogroups using 11 defining SNPs and a deletion. 145 DNA samples were unambiguously assigned to one of 12 haplogroups (three haplogroups were not present) and these were associated with the self-declared genealogy of the donor and that of their mother and maternal grandmother. The assay demonstrated the potential to discriminate between self-declared African, Asian or ‘non-indigenous Australian’ (European) ancestry with 71%, 88% and 90% accuracy, respectively. Larger DNA sample populations that include Y chromosome and autosomal markers have the potential to predict ancestry with finer detail.