Yes / Sampling of dentine for stable carbon (δ13 C) and nitrogen (δ15 N) isotope ratios in the direction of tooth growth allows the study of temporal changes to the diet and physiological stress of an individual during tooth formation. Current methods of sampling permanent teeth using 1mm increments provide temporal resolution of six - nine months at best depending on the tooth chosen. While this gives sufficient sample sizes for reliable analysis by mass spectrometry, sectioning the dentine across the incremental structures results in a rolling average of the isotope ratios. A novel method of incremental dentine collagen sampling has been developed to decrease the collagen increment size to 0.35mm along the incremental structures thus reducing averaging and improving the temporal resolution of short-term changes within the δ13 C and δ15 N values. This study presents data for a MicroMill-assisted sampling method that allows for sampling at 0.35mm width x 1mm depth increments following the incremental growth pattern of dentine. A NewWave MicroMill was used to sample the demineralised dentine section of modern donated human third molars from Sudan and compared to data from the same teeth using the 1mm incremental sectioning method 2 from Beaumont et al. (2013). The δ13 C and δ15 N isotopic data showed an increased temporal resolution, with each increment providing data for two-four months of dentine formation. The data show the potential of this method for studying dietary reconstruction, nutritional stress, and physiological change with greater temporal resolution potentially to seasonal level and with less attenuation of the δ13 C and δ15 N values than was previously possible from human dentine.

Sampling methods for dentine and bone collagen have been evolving for several decades. Incremental dentine collagen sampling and bone collagen sampling have been limited by the available technology throughout that time. As the technology for isotope ratio mass spectrometry analysis improves, the sampling methods should improve as well. This research focused on developing a new incremental dentine collagen sampling method and bone collagen microsampling method for stable isotope analysis. This research aimed to increase the temporal resolution of incremental dentine collagen sampling and provided sequential collagen sampling from bone collagen for stable carbon and nitrogen isotope analysis while limiting the destructive nature of bioarchaeological analysis. It was determined that the temporal resolution for incremental analysis could be reduced to approximate three months, opposed to the nine months found in other sampling methods. It was also determined that detailed isotopic data could be obtained from bone collagen when sampling the microstructures. The increased amount of isotopic data from the bone collagen was an improvement on the commonly used bulk collagen sampling. This research can be utilised to answer several of the questions that archaeologists have been asking about past populations. Isotopic analysis using the methods developed in the research can provide a more detailed observation of the diet and health of past populations. In addition, the developed methods for bone and dentine collagen reduced the amount of tissue subjected to destructive analysis.

No description available.

Par l’intermédiaire d’analyses isotopiques de l’émail et de la dentine (δ13C, δ15N, δ18O), l’étude vise à reconstituer pour la première fois les schémas de mobilité et les pratiques alimentaires au cours de l’enfance d'une population inhumée au cimetière catholique du faubourg de Saint-Antoine (1799 -1854) (N=24). Ce dernier est un site clé, lié à la transition de la ville de Montréal vers l'industrialisation et reflète une croissance démographique exponentielle reliée au flux migratoire accru en provenance surtout des îles Britanniques (Écosse, Angleterre, Irlande), des États-Unis, du milieu rural canadien et d’autres régions possiblement (Afrique, Caraïbes). De plus, six individus, victimes du naufrage du Carrick of Whitehaven sur la côte gaspésienne (Cap-des-Rosiers, 1847), ont fourni des données sur les migrants irlandais de première génération. Pour tous les individus, un seul échantillon a été prélevé pour l’émail (couronne inférieure) et la dentine (racine/apex) sur une prémolaire ou deuxième molaire permanente pour couvrir une période de vie entre 2 ans et l’adolescence. En plus, pour quatre individus, deux méthodes de micro-échantillonnage en séquence de la dentine (micro-poinçon, micro-tranche) ont été réalisées pour comparer leur efficacité et obtenir des données plus détaillées. Les résultats généraux suggèrent une diversité alimentaire au cours de l’enfance basée sur l’origine des personnes : le régime alimentaire à Montréal était principalement basé sur les ressources en C3, avec l’ajout de ressources en C4 pour les locaux et les gens originaires du Haut-Canada; et l’apport en aliments carnés était plus important chez les immigrants des îles Britanniques ou des États-Unis. Ces faits concordent avec les sources historiques qui mentionnent un afflux de migrants et une alimentation diversifiée selon les groupes culturels à Montréal. Les données isotopiques observées pour Cap-des-Rosiers sont beaucoup plus homogènes qu’à Saint-Antoine, car elles reflètent un événement migratoire ponctuel. Comme trois individus de Saint-Antoine ont des résultats isotopiques très similaires à ceux de Cap-des-Rosiers, il est proposé qu’il s’agisse d’Irlandais voire de personnes ayant un parcours de vie similaire à des migrants venus des îles Britanniques. Finalement, l’un d’entre eux (9M-S2) a révélé grâce aux micro-tranches (technique la plus adaptée pour obtenir des variations temporelles très fines) une augmentation du δ15N vers l’âge de 4 ans, possiblement relié à un stress physiologique (ex. famine). / By using isotopic analyses of enamel and dentin (δ 13C, δ 15N, δ 18O), this study aims to reconstruct for the first time the mobility patterns and dietary practices during infancy of a population buried in the Saint Antoine Catholic cemetery (1799 -1854) (N=24). The latter is a key site linked to the city of Montreal's transition to industrialization and reflects a period of exponential population growth linked to increased migration especially from the British Isles (Scotland, England, Ireland), the United States, rural Canada, and to a few other regions possibly (Africa, Caribbean). Moreover, six individuals, victims of the shipwreck of the Carrick of Whitehaven on the Gaspé Coast (Capdes-Rosiers, 1847), provided data on first-generation Irish migrants. For all individuals, a single sample was taken from enamel (lower crown) and dentin (root/apex) of one permanent premolar or second molar to cover a life span between 2 years and the adolescence. In addition, for four individuals, two methods of sequential micro-sampling of dentin (micro-punch, micro-slice) were carried out to compare their effectiveness and obtain detailed data. Overall results suggest dietary diversity during childhood based on people's origins: the diet in Montreal was mainly based on C3 resources, with the addition of C4 resources for locals and people from Upper Canada (Ontario); and meat intake was higher among immigrants from the British Isles or the United-States. These facts are consistent with historical sources that mention an influx of migrants and a diversified diet among the cultural groups of Montreal. The isotopic data observed for Cap-des-Rosiers are much more homogeneous than for Saint-Antoine, reflecting one tragic migratory event. As three individuals from Saint-Antoine have isotopic results very similar to those from Cap-des-Rosiers, it is proposed that they are Irish or people with a life history similar to migrants from the British Isles. Finally, one of them (9M-S2) revealed an increase in δ 15N around the age of 4 years old, possibly linked to physiological stress (e.g. famine) thanks to micro-slicing (the most suitable technique for obtaining very detailed temporal variations).