Evaluating Morphoscopic Trait Frequencies of Southeast Asians and Pacific Islanders

When assessing ancestry in a forensic context, individuals are generally classified into one of four categories: belonging to European, African, Asian, or Native American ancestry. With only these four assessments, individuals from Southeast Asia and the Pacific Islands are usually phenotypically classified as Asian. While the oceanic regions of Southeast Asia and the Pacific Islands will most likely have trait frequencies similar to those of mainland Asia because of their shared ancestral lineages, there is still a great deal of variability in this region that could cause these trait frequencies to differ. To address this variability, sixteen morphoscopic traits were recorded using the program Osteoware (2011). Skeletal specimens include (n=135) from the Smithsonian National Museum of Natural History and (n=30) from the University of Pennsylvania Museum of Archaeology and Anthropology, for a total of (n=165). Populations collected include individuals from Island Southeast Asia, Melanesia, and Polynesia. These were compared closely with data on 7 morphoscopic traits collected for mainland Asians (n=74), as well as for 5 morphoscopic traits of larger groups found throughout the world: American Indian, African American, European American, and Eskimo groups. The results indicated that the trait distributions of the Pacific were not similar to any of the other larger groups of the world for all five traits examined. Further, it was found that 7 out of 9 traits were significantly different in their frequencies between mainland Asians and groups of the Pacific. A clinal pattern of trait expression was noted across the geography on a west-east orientation for 6 traits. In correspondence analyses and cluster analyses, the Southeast Asians, Melanesians, and Polynesians were found to be more similar to each other than to mainland Asia. The Melanesians and the Southeast Asians showed the greatest correlation of morphoscopic trait frequency distribution. Overall, the Pacific group had a higher inclination for larger posterior zygomatic tubercles and a much higher prevalence of a straight zygomaticomaxillary suture than other groups of the world examined. The expression of these traits should be kept in mind when estimating the biological affinity of an individual