rASUDAS A New Web-Based Application for Estimating Ancestry from Tooth Morphology

• NCJ Number: 310033
• Journal: Journal of Forensic Sciences Volume: 1 Issue: 1 Dated: January 2018
• Author(s): Richard Scott; Marin A. Pilloud; David Navega; João D'Oliveira Coelho; Eugénia Cunha; Joel D. Irish
• Date Published: January 2018
• Grant Number(s): 2017-DN-BX-0143
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical)
• Award: A Dental Anthropological Databank for Use in the Statistical Estimation of Ancestry and Sex in Forensic Anthropology

Annotation

This article introduces rASUDAS, a new web-based application for estimating ancestry from tooth morphology.

Abstract

This paper presents a new web-based application (rASUDAS) that estimates the ancestry of unknown individuals based on their suite of tooth crown and root traits. The use of crown and root morphology to estimate population relationships has a long history in dental anthropology. Over the past two decades, methods employing dental morphology within forensic anthropology have been formalized with the incorporation of statistical models. The application utilizes 21 independent traits that were scored following the Arizona State University Dental Anthropology System (ASUDAS). The reference sample represents approximately 30,000 individuals from seven biogeographic regions. A naive Bayes classifier algorithm was created in the R open-source programming language to assign posterior probabilities for individual group assignment. To test the application, 150 individuals were selected from the C. G. Turner II database with the proviso that an individual had to be scored for a minimum of 12 of the 21 traits. In a seven-group analysis, the model correctly assigned individuals to groups 51.8% of the time. In a four-group analysis, classification accuracy improved to 66.7%. With three groups, accuracy was at 72.7%. It is still necessary to validate the program using forensic cases and to augment the reference sample with modern skeletal data. However, results from the beta version of rASUDAS are presented as proof of concept on the potential of dental morphology in ancestry estimation in forensic contexts. (Published Abstract Provided)