Subadult Ancestry Estimation Using Craniometrics, Macromorphoscopics, Odontometrics, and Dental Morphology

Forensic and biological anthropologists do not estimate ancestry in subadults, nor do they know the age at which ancestry estimation is feasible. A lack of subadult resources leads to this type of uncritical dependence on conjecture and anecdotal data in which researchers claim there is a lack of distinctive phenotypic features before adulthood. There is a critical need to understand the ontogenetic trajectories of phenotypic diversity to ultimately incorporate ancestry estimation into the subadult biological profile, subsequently increasing positive identification rates. Four different data types, including craniometrics, odontometrics, macromorphoscopics, and dental morphology will be collected on a large and geographically diverse sample of US children aged 0 to 20 years (n > 2000). All data will be collected from CT scans generated at two medical examiner’s offices (Office of the Medical Investigator, New Mexico, and Office of the Chief Medical Examiner, Maryland) and one dental school (The University of Texas Health Science Center at San Antonio, School of Dentistry). Data will cover geographically and socially diverse populations ensuring the true demographic diversity of the US is captured.

There are two primary aims: 1) to collect craniometric, macromorphoscopic, odontometric, and dental morphological data on individuals between birth and 20 years of age to establish the age at which each trait or indicator presents with comparable frequencies, stability, and/or multivariate distributions as it does in the adult population and 2) to determine the age at which forensic anthropologists can confidently estimate ancestry using both single and multiple indicators and traits, and quantify the predictive ability of each indicator throughout ontogeny. Analyses will include chi-square and Kruskal-Wallis for the ordinal data, anovas and canonical variate analysis for the continuous data, and wire frame visualizations using three-dimensional landmark data to satisfy Aim #1. Random forest models will be used to satisfy Aim #2.

The two expected outcomes yielded by this innovative project are a comprehensive evaluation of the ontogenetic appearance of metric and morphological cranio-facial phenotypic traits among subadults from diverse backgrounds in the US (Aim #1) and documenting the age at which forensic anthropologists can estimate ancestry in skeletally immature remains all the while increasing our knowledge on the predictive ability of indicators throughout ontogeny (Aim #2).

Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14).

CA/NCF