Ressource pédagogique : Tracing Human Ancestral Migration from its Symbiotic Bacteria / Alexia Nguyen Trung

Informations pratiques sur cette ressource

Description de la ressource pédagogique

Description (résumé)

Tracing Human Ancestral Migration from its Symbiotic Bacteria / Alexia Nguyen Trung, in colloque "1st Virtual Conference for Women Archaeologists and Paleontologists. Nouveaux apports à l’étude des populations et environnements passés" organisé par le laboratoire Travaux et Recherches Archéologiques sur les Cultures, les Espaces et les Sociétés (TRACES) de l’Université Toulouse Jean Jaurès et le laboratoire Paléontologie Évolution Paléoécosystèmes (PALEVOPRIM) de l'Université de Poitiers, sous la responsabilité scientifique de Julie Bachellerie, Ana Belén Galán López (Traces), Émilie Berlioz et Margot Louail (Palevoprim). Université Toulouse Jean Jaurès, 8-9 mars 2021. Session 2 : Occupation of territories and population mobility. [Conférence enregistrée en distanciel]. Our understanding of the history of human migrations around the globe has greatly benefited from the development of human population genetics. It has revealed the routes of colonization and striking events of admixture of populations on the way. Many species have accompanied humans on their journey, particularly microbes closely associated to their human host. H. pylori is present in the stomach of 50% of humans. Its transmission is vertical, since it occurs particularly during childhood within the family, limiting the spread of a strain to its carrier human group. Previous work has established that its presence in Homo sapiens dates back to before the major human migrations and that H. pylori accompanied its host during the settlement process of continents, to the point that the phylogeny traces in broad lines the history of human migrations since Out Of Africa. We have developed tools to reconstruct the history of bacterial genomes and particularly Horizontal Gene Transfer, which is the ability of bacteria to acquire genetic material from other strains or species. We have shown the efficiency of these methods for retracing ancient contacts and dating the history of free-living bacteria and we use the same approach to explore the history of H. pylori. By reconstructing the history of a sample of representative H. pylori strains, we use these methods to detail the historical contacts between strains and interpret these events in terms of contacts between ancestral human populations. We focus on the complex history of European populations taking advantage of the ancient genome of H. pylori extracted from Ötzi, the iceman, which dates back to around 3000 BCA. Ötzi's H. pylori shows clear relationships with strains that are found today in Asia. During this presentation we will detail the method and discuss our results on the history of human mobilities in Europe, through the prism of symbiotic bacteria.

"Domaine(s)" et indice(s) Dewey

• Bactéries (579.3)
• Paléolithique (930.12)
• Influences du milieu sur le physique des hominidés, Biologie et écosystème humain (599.95)

Thème(s)