Biological Distance Analysis based on Anatomical Variations in Populations of Southern France in Medieval and Modern Times

One of the key questions that biological anthropology seeks to answer is the biological relationship between individuals. To answer this question, biological distance (biodistance) analysis is the tool that has been developed in recent years. Biodistance analysis use phenotypic or morphological data to estimate a genetic similarity between or among populations. The aim of this study is to test whether the medieval and modern populations of southern France are biologically and significantly similar. The morphological tool used to answer to our aim is asymptomatic variation. Skeletal and dental asymptomatic variations (AV) are described as non-pathological and polyfactorial traits found on the whole skeleton. Their expression is controlled by genetic and environmental factors. In this case, traits whose expression is mainly under genetic control have been selected. On four samples from two osteoarcheological collections, 94 skeletal and dental AVs have been rated, i.e., 198 ratings made on each skeleton. The mean measure of divergence (MMD) statistic has been used to analyze the biodistance. To use it effectively, primary statistics were performed to select only the most relevant traits: present in more than one individual in each sample, traits not influenced by the sex of the individual, and traits not correlated with each other. The biodistance has been estimated between four populations: two from the cathedral of Digne-les- Bains, from a medieval and a modern period, and two from the Saint-Michel cemetery in Toulouse, from two different modern period. The results show a certain similarity of the populations of Southern France. Only the medieval population of Digne and the more modern population of Toulouse are significantly different morphologically. In order to confirm or refute the results obtained, we are currently conducting a DNA analysis of the samples

Proposition d’une démarche commune pour la sélection de variations asymptomatiques osseuses et dentaires répétables et reproductibles en anthropologie biologique

International audienceAsymptomatic variations (AV) in bones and teeth are widely used in biological anthropology, particularly to understand intra- and inter-population affinities.This study focuses on the first step of any study: the repeatability and reproducibility of the method implemented. Using the Kappa coefficient, the reliability of 198 variables divided into three anatomical areas (cranial, post-cranial and teeth) was analyzed. The sample used was selected among the best represented and best preserved individuals of the Notre-Dame-du-Bourg osteo-archaeological collection (Digne-les-Bains, medieval and modern period). The analyses were performed after four rounds of scoring (three observers), and when more than 20 observations of polymorphic variations were obtained. The quality of agreement was established according to the Fleiss et al. scale (2003). Although missing data were a hindrance in this study, several proposals were made to overcome the problem. We also highlight and discuss the fact that experience has an impact on the observation of qualitative variables. The outcome is a proposal for a protocol based on selecting repeatable and reproducible AVs to normalize comparisons between studies in both osteoarchaeological and forensic contexts.Les variations asymptomatiques (VA) osseuses et dentaires sont grandement utilisées en anthropologie biologique, notamment pour appréhender les affinités intra- et inter-populationnelles. Cette étude se concentre sur la première étape de toute étude : la répétabilité et la reproductibilité de la méthode mise en place. À partir de l’utilisation du coefficient de Kappa la fiabilité de 198 variables réparties en trois zones anatomiques (crâne, post-crâne et dents) a été analysée. L’échantillon utilisé a été sélectionné parmi les individus les mieux représentés et conservés de la collection ostéo-archéologique Notre-Dame-du-Bourg (Digne-les-Bains, périodes médiévale et moderne). Les analyses ont été réalisées, suite à quatre séries de cotations (trois observatrices), et lorsque plus de 20 observations sur des variables polymorphiques ont été obtenues. La qualité de l’accord a été établie selon l’échelle de Fleiss et al. (2003). Bien que les données manquantes aient été un frein dans cette étude, plusieurs propositions sont faites afin de palier ce phénomène. De plus, nous mettons en avant et discutons le fait que l’expérience a un impact sur l’observation des variables qualitatives. Au final, un protocole basé sur la sélection de VA répétables et reproductibles est proposé pour normaliser les comparaisons entre études dans un contexte aussi bien bioarchéologique que médico-légal

Quelles sont les variations asymptomatiques crâniennes, post-crâniennes et dentaires effectivement répétables et reproductibles, dans le cadre d’un échantillon bioarchéologique ?

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