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Errors in ancestry prediction for historical military casework result in soldiers unable to be interred to the country they fought and died for. Australian WWII soldiers with varying degrees of European and Asian heritage are expected in the remains recovered in the Asia-Pacific, representing the greatest risk of error for Unrecovered War Casualties-Army (UWC-A). Previous research using the Ghaiyed population-specific panel (GPSP), on a modern British sample, demonstrated less variation in family-level admixture compared to four global ancestry panels. This suggested that the targeting of specific populations of interest may improve accuracy, although an evaluation using a sample of WWII-era European-Australians (W2A) with varying degrees of family-level admixture was required. This paper outlines the development of an ancestry prediction strategy using a W2A sample (non-admixed), and simulation of 4,000 genotypes representing Australian pedigrees with one Japanese ancestor (great-great-grandparent, great-grand-parent, grandparent, and parent). All great-great-grandparent to grandparent profiles were accurately predicted as W2A individuals, and although admixture at the parent level could not be resolved, no profiles were incorrectly assigned Japanese ancestry. The GPSP provided more informative predictions in contrast with the mitochondrial DNA/Y-chromosome lineage approach currently used by UWC-A as the GPSP provides an approximately 75% improvement. [ABSTRACT FROM AUTHOR]

Unrecovered War Casualties – Army (UWC-A) is part of the Australian Defence Force (ADF) and investigates unaccounted for Australian soldiers from previous conflicts. In the Asia-Pacific region of WWII, DNA is often the only method available to predict the ancestry of remains. UWC-A specifically apply mtDNA/Y-DNA lineage testing which is estimated to predict ancestry accurately for only 23.4% of cases. This research presents a population-specific ancestry prediction strategy targeted to meet UWC-A needs and may ultimately lead to direct identification through further familial testing. Structure analyses indicated that all samples representing the UWC-A scenario (n = 195; British and Japanese samples) were correctly assigned. The use of the Ghaiyed population-specific panel (GPSP) showed an increase in thelowest membership profile for each group greater than was observed for other ancestry panels. This comparison demonstrated an increase in the minimum membership proportion in each group (14.3% for British and 18.1% for Japanese individuals). The Genomic Differentiation Index (GDI) indicated that the optimum differentiation between the GBR and JPT groups could be achieved using the GPSP. Six phenotype SNPs were used for the prediction of blue/brown eye colour and light/dark hair. This ancestry/phenotype prediction strategy will be evaluated on a historically relevant sample in the future. [ABSTRACT FROM AUTHOR]

Mitochondrial DNA (mtDNA) is used for identification of Australian military personnel whose remains are recovered from historical conflicts. A mtDNA sample database does not exist for Australian soldiers that served in World War I (WWI), World War II (WWII) and the Korean War, meaning it is unknown what common haplotypes may have existed among these soldiers, risking identification errors. Haplotype diversity (position 16,024 to 548) was examined in a sample of 254 unrelated WWII-era European-Australians. Of these, 220 different haplotypes were observed, and it is estimated that between 18% and 29% of Australian soldiers who served in historical conflicts have common haplotypes (95% CI). This research demonstrates that mtDNA control region analysis of historical military remains will provide a lower than expected power of discrimination given the population structure of the time, and enlistment policies targeting Australians of European decent. The point estimates for 52% of the common haplotypes obtained in the historical European-Australian sample were not represented in the confidence intervals for European and Western-European EMPOP data. Creation of targeted sample data reflecting correct ancestry of the WWI and II soldiers and additional mtDNA and Y-STR analysis are essential to avoid misidentification of Australian soldiers from historical conflicts. [ABSTRACT FROM AUTHOR]