Craniometric estimation of ancestry in Thai and Japanese individuals

Abstract

© 2020, © 2020 Australian Academy of Forensic Sciences. There are currently no forensic methods for distinguishing Thais from other individuals of Asian ancestry using craniometrics. Of foreigners visiting or living in Thailand, Japanese people predominate. Remains of Japanese soldiers from the Second World War were excavated in northern Thailand, and hundreds more are thought to have disappeared in this area and nearby countries. This research aims to develop new formulae for ancestry estimation of skulls suspected to be Thai or Japanese. This was achieved by measuring 440 Thai and Japanese skulls. Stepwise discriminant analysis created four formulae. The first formula is for a complete skull, with predicted and correct classification accuracy of 89.3% and tested accuracy of 91.2%. The second formula, cranium only, gave 84.3% predicted and correct classification accuracy and tested accuracy of 85.3%. The third formula, for a male skull, gave predicted and correct classification accuracy of 92.0% and tested accuracy of 85.3%. The fourth formula, for a female skull, produced 89.8% predicted and correct classification accuracy and tested accuracy of 88.2%. Differentiating between Asian subgroups is challenging, but this study demonstrates the potential to distinguish Thai from Japanese individuals in forensic applications. It can be used to clarify ancestry of ‘Asian’ unclaimed bodies found in Thailand.