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

Abstract

The use of dental morphology to estimate ancestry has a long history within dental anthropology. Over the past two decades methods employing dental morphology within forensic anthropology have become more formalized with the incorporation of statistical models. We present here on a new application (rASUDAS) to estimate ancestry of unknown individuals using crown and root morphology of the dentition. The reference sample is composed of 21 traits based on the Arizona State University Dental Anthropology System and represents approximately 30,000 individuals from seven geographic regions. The statistical program was created in R and uses a naïve Bayes classifier algorithm to assign posterior probabilities for individual group assignment. A random sample of 150 individuals from the dataset was chosen and input into the program. In a sevengroup analysis, the model was correct in group assignment 51.8% of the time. In a four-group analysis, classification improved to 66.7%, and with only three groups considered the accuracy improved to 72.7%. It is still necessary to validate the program using forensic cases and to augment the reference sample with modern skeletal data. However, we present these results as a proof of concept of the statistical application and the use of dental morphology in the estimation of ancestry.

Variation in dental morphology and inference of continental ancestry in admixed Latin Americans

“…Because of the great preservation of teeth and their considerable morphological variation dental traits have been used extensively in human evolutionary studies, including the analysis of archaeological remains and the diversity of contemporary populations (Guatelli‐Steinberg, ; Irish & Scott, ; Scott & Turner, ). The differentiation of dental traits among continental populations has also been exploited, usually in a forensic setting, for the purpose of assignment of ancestry to human remains of unknown origin (Alsoleihat, ; Edgar, , , , ; Irish, ; Scott et al, ; Scott & Turner, ). Such studies have mostly focused on establishing individual ancestry with reference to discrete population categories, such as those defined in the US census (e.g., European‐Americans and African‐Americans).…”

Outline Shape Analysis on the Trochlear Constriction and Olecranon Fossa of the Humerus: Insights for Sex Estimation and a New Computational Tool,

“…After selecting the best predictive model based on overall accuracy, sensitivity and specificity performance metrics, and the parsimony principle (i.e., among equally good competing models, choose the simplest one), a web application was developed using the Shiny package for R . Following a recent trend in forensic anthropology, which attempts to make complicated statistical models more accessible and easier to utilize through interactive online applications , the new contribution is an interactive model using PC3 and PC5 to simulate shapes in order to estimate sex and is available online at http://osteomics.com/Ammer-Coelho free to use for forensic anthropologists and anyone interested in the matter (Fig. ).…”

Population history of southern Italy during Greek colonization inferred from dental remains

“…This assumption generally holds true when using dental nonmetric trait data as discussed in the previous section (see Appendix S1, Figure S1 and Appendix S2, Sheet 1). Because naïve Bayes classification is conceptually simple, allows for missing variables, and has few assumptions, it is widely used in classification studies based on dental nonmetric trait data (Bailey, Weaver, & Hublin, ; Edgar, ; Herrmann, Plemons, & Harris, ; Scott et al, ).…”