Navigating Identity: The Intersection of Social and Biological Identity from the World War II Battle of Tarawa.

The 1943 Battle of Tarawa resulted in the loss of approximately 1,000 US service members on or around Betio Island, Tarawa Atoll, Republic of Kiribati. Nearly half these casualties were accounted for after the battle. The Defense POW/MIA Accounting Agency (DPAA) has worked to identify the remaining ∼510 unaccounted-for service members and has successfully identified ∼160 service members to date. Demographic data pulled from historical documentation of the US losses indicate a relatively homogeneous population (99% White, 81% 17-23 years of age, and only two individuals with a documented religious preference other than Protestant or Catholic). Using this demographic data as a framework, three case studies are presented to demonstrate how a holistic biosocial approach to building identity could facilitate forensic identifications. The temporal and sociocultural contextualization of analyses enables anthropologists to navigate inconsistencies between 21st-century and historical (1940s) social identity concepts to overcome challenges to identification. The case studies demonstrate how biological evidence, genetic evidence, and material evidence (material culture) differently contribute to the social identity of an individual and can impact identification efforts when analytical conclusions are incongruent with historical documentation. The first case of US Battle of Tarawa casualties examines how morphometric biological affinity assessments are biased by the fluidity of social identity concepts when complex morphological and metric indicators of biological affinity are not represented in historical race categories. The second case demonstrates how biogeographic genetic affinity predictions, through a discussion of the G2a4 haplogroup, need to be examined holistically in the context of other lines of evidence. The third case highlights how material evidence can further define social identity beyond physicality, genetic structure, and race. The challenges of interpreting identity from human remains, as highlighted through these examples, are commonly encountered by anthropologists working in disaster victim identification and other humanitarian contexts. Thus, it is imperative for anthropologists to be self-aware of implicit biases toward the current prevailing definitions of biological and social identity and to consider historical perceptions of identity when working in these contexts.

Comparing Genetic Variation among Latin American Immigrants: Implications for Forensic Casework in the Arizona- and Texas-Mexico Borderlands.

The humanitarian crisis on the US-Mexico border is a long-standing and evolving crisis in which nearly 8,000 deaths have been reported in the last two decades. These deaths are largely distributed across the Arizona-Mexico and Texas-Mexico border regions, where demographic trends for immigrants attempting to cross into the United States have shifted dramatically. The demographic change and volume of immigrants seeking shelter in the United States present new challenges for the forensic practitioners entrusted with the identification of individuals who lose their lives during the final segment of their journey. Within this border context, this study investigated how genetic variation inferred from forensically significant microsatellites can provide valuable information on regions of origin for unidentified remains at the group level. To explore how to mobilize these genetic data to inform identification strategies, the authors conducted a comparative genetic analysis of identified and unidentified immigrant cases from the Arizona- and Texas-Mexico contexts, as well as 27 other Latin American groups. Allele frequencies were utilized to calculate FST, and relationships were visually depicted in a multidimensional scaling plot. A Spearman correlation coefficient analysis assessed the strength and significance of population relationships, and an agglomerative clustering analysis assessed population clusters. Results indicate that Arizona-Mexico immigrants have the strongest relationship (>80%) with groups from El Salvador, Guatemala, Mexico, and an indigenous group from southern Mexico. Texas-Mexico immigrants have the strongest relationships (>80%) with groups from Belize, Colombia, Costa Rica, El Salvador, Guatemala, Honduras, and Nicaragua. These findings agree with, and are discussed in comparison with, previously reported demographic trends, population genetics research, and population history analyses. The authors emphasize the utility and necessity of coupling genetic variation research with a nuanced anthropological perspective for identification processes in the US-Mexico border context.