Improving the strategy to identify historical military remains: a literature review and Y-STR meta-analysis

The identification of historical military remains by Unrecovered War Casualties-Army (UWC-A) currently relies on Y-chromosome Short Tandem Repeat (Y-STR) testing when maternal relatives are not available, or when a mitochondrial DNA match does not provide sufficient certainty of identification. However, common Y-STR profiles (using Yfiler™) between sets of remains or families often prevent identification. To resolve these cases, an investigation of additional Y-DNA markers is needed for their potential inclusion into the DNA identification strategy. The number of genetic transmissions between missing soldiers and their living relatives needs to be considered to avoid false exclusions between paternal relatives. Analysis of 236 World War I/II (WWI/II) era pairs of relatives identified up to seven genetic transmissions between WWII soldiers and their living relatives, and nine for WWI. Previous Y-STR meta-analyses were published approximately 10 years ago when rapidly mutating markers were relatively new. This paper reports a contemporary literature review and meta-analysis of 35 studies (which includes 23 studies not previously used in meta-analysis) and 23 commonly used Y-STR's mutation rates to inform the inclusion of additional loci to UWC-A's DNA identification strategy. Meta-analysis found mutation data for a given Y-STR locus could be pooled between studies and that the mutation rates were significantly different between some loci (at P < 0.05). Based on this meta-analysis, we have identified two additional markers from PowerPlex® Y23 for potential inclusion in UWC-A's identification strategy. Further avenues for potential experimental exploration are discussed.

Key points

From 236 UWC-A pairs of relatives, we observed up to nine genetic transmissions between WWI soldiers and their living relatives, and seven for WWII.MedCalc® software for meta-analysis utilizing the Freeman-Tukey transformation was run, which analysed 35 published studies and 23 commonly used loci. Previous Y-STR mutation rate meta-analyses are now 10 years old; this paper includes 23 studies that were not included in previous meta-analyses.Through meta-analysis, we identify two markers from PowerPlex® Y23 for potential inclusion in UWC-A's historical remains identification strategy (alongside Yfiler™). We discuss potential next steps for experimental exploration of additional Y-DNA markers.

"Lest we forget": An overview of Australia's response to the recovery and identification of unrecovered historic military remains

The Australian Defence Force (ADF) is responsible for the recovery and identification of its historic casualties. With over 30,000 still unrecovered from past conflicts including World War One (WW1) and World War Two (WWII), the Australian Army and Royal Australian Air Force have teams that research, recover, identify and oversee the burial (or reburial) of the remains of soldiers and airmen who continue to be found each year. The Royal Australian Navy is also responsible for its unrecovered casualties. Collectively the priorities of the various services within the ADF are the respectful recovery and treatment of the dead, thorough forensic identification efforts, resolution for families and honouring the ADF's proud history of service and sacrifice. What is unique about the approach of the ADF is that the respective services retain responsibility for their historic losses, while a joint approach is taken on policies and in the utilisation of the pool of forensic specialists. Section One describes the process undertaken by the Australian Army in the recovery, identification and burial or repatriation of soldiers through its specialised unit Unrecovered War Casualties - Army (UWC-A). Section Two describes the role of the Royal Australian Air Force in the recovery of aircraft and service personnel through their specialised unit Historic Unrecovered War Casualties - Air Force (HUWC-AF). An overview of the operations of each service and case studies is presented for each section.