Resolving mitochondrial haplogroups B2 and B4 with next-generation mitogenome sequencing to distinguish Native...

Mitochondrial haplogroup information can be useful in forensic contexts that rely primarily on mitochondrial DNA (mtDNA) testing, which often involve limited or degraded DNA. Due to the phylogeographic patterning of mtDNA in human populations, mitochondrial haplogroups are indicative of maternal ancestry (as mtDNA is a maternally inherited marker). In certain circumstances, maternal ancestry inferred from mitochondrial haplogrouping could be beneficial to forensic investigations. For example, ancestry information could assist in the identification of unknown service members from past conflicts, such as the World War II Battle of Tarawa involving American and Japanese forces. In this context, it could be useful to distinguish Native American mtDNA from Asian mtDNA to bolster the anthropological and circumstantial evidence leading to an identification or foreign national determination. Although most of the founding Native American haplogroups contain diagnostic variants in the mitochondrial control region (CR), haplogroup B2 does not, and this makes it more difficult to distinguish B2 from the parental B4 and closely related B4b haplogroups found in Asia. In this paper, the amount of mtDNA information required to distinguish Native American haplotypes from Asian haplotypes within haplogroup B was examined. Fifty-six samples belonging to subtypes of B2 and B4 were sequenced for the entire mitogenome. Haplogroups were estimated from three ranges of mitochondrial DNA (HV1 and 2, CR, and full mitogenome). Half of the samples could not be precisely haplogrouped without full mitogenome data, although enough variants were often provided to make an accurate B2 versus B4 distinction. Native American B2 haplotypes were distinguishable using CR data alone in 82% of samples, though the remaining samples required full mitogenome data for haplogroup B2 designation. The use of full mitogenome data consistently enables accurate haplogroup determination, and opens the possibility for gaining information on maternal ancestry.