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oai:orbi.ulg.ac.be:2268/1395692026-09-01T13:26:54Zcom_f00col_f03class_f

doctoral thesis http://purl.org/coar/resource_type/c_db06 info:eu-repo/semantics/doctoralThesis restricted access http://purl.org/coar/access_right/c_16ec info:eu-repo/semantics/restrictedAccess Apport de données d’ADN nucléaire à la Phylogénie et à la Biologie de la Conservation des Ursidae Contribution of DNA nuclear sequences to the phylogeny and the conservation biology of Ursidae Pagès, Marie Hänni, Catherine Jaeger, Jean-Jacques 2007-10-30 https://orbi.uliege.be/handle/2268/139569 info:hdl:2268/139569 fr Ursidae, ADN ancien, Hibernation, Phylogénie moléculaire des Ursidae, SRY, Sexage moléculaire, Génétique de la Conservation, Paléogénétique Life sciences Sciences du vivant Currently, the Ursidae family includes eight bear species. They represent an unusual family within the order of the Carnivores because of their peculiar physiological adaptations related to hibernation. These physiological features, unique in the animal kingdom, make bear a unique model for medical research in full expansion because of its putative clinical applications. This point will be developed in introduction of this manuscript. Surprisingly, the phylogenetic relationships within the extant Ursid representatives remain unclear. In order to clarify their phylogeny, we sequenced 12 nuclear genes for all the Ursid species (nearly 8 kilobases corresponding to 6 genes implied in the pathway of the thyroid hormones, 3 genes specific to the sexual chromosomes, and 3 other autosomal genes). By concatenating these new data with those available in the sequence databanks, phylogenetic reconstructions (maximum likelihood and bayesian analyses) were carried out on a nuclear DNA dataset of 10 kilobases. It was then possible to refine the phylogeny of the Ursidae family. In addition, based on the study of the genes SRY (Sex determining region of the Y chromosome), ZFX/ZFY (Zinc Finger protein) and AMLX/AMLY (Amelogenine), we developed a reliable method to determine the sex of Ursidae based on the analysis of DNA extracted from non invasive samples such as hairs or faeces. If this tool has obvious implication for the conservation biology of Ursidae (most of the extant species are threatened with extinction), it also opens new prospects in palaeontology. This kind of analysis was indeed applied to samples of fossils of North African brown bears (Ursus arctos). The last chapter of this manuscript illustrates how the palaeogenetics can help palaeontology interpreting the variability of fossil forms. Université Montpellier 2