Analysis of ancient DNA from teeth of human remains excavated from the Gallo-Roman necropolis on Rue Perdue in Tournai

This study was aimed at applying molecular biology techniques to address archaeological questions that could not be answered otherwise through classical historical and archaeological methods. Thanks to genetic analyses performed during this work on teeth of human remains excavated between 1989 and 2010 from a Gallo-Roman necropolis discovered in Tournai (Belgium), it has been possible to acquire new information on populations living in Tournai during the Late Roman Empire (3rd-4th century AD). The first objective of this study was to assess the feasibility of the extraction and analysis of ancient mitochondrial and nuclear DNA from teeth. After extracting and sequencing ancient DNA, we evaluated the authenticity of the results. DNA was successfully extracted. Only a few cross-contaminations were reported among some sequences amplified by PCR. The second objective addressed the result contribution to archaeological studies. It aimed at answering several questions. The geographical origin of individuals was first investigated by using mitochondrial haplogroups and measurements of Strontium isotopes (87Sr/86Sr). An accurate geographical origin of individuals could not be determined when using these haplogroups. However, Sr ratio analyses helped to restrict the plausible origins by excluding certain regions such as Northern Europe, Spain or the Alps. These results also demonstrated that individuals were not native of the same region. This would suggest that population movements had occurred at least at the regional scale of Tournai and its surrounding regions. Based on mitochondrial haplogroups, the concentrations did not appear to be associated with family clusters. The presence of family vaults based on maternal lineages could be excluded. Finally, an analysis of nuclear DNA data enabled sex identification of some individuals, which confirmed the results of previous anthropological studies. This project outlined the relevance and the potential of the molecular biology techniques applied to the archeological field. The advanced technology could help to confirm or not historical assumptions, to complement and acquire new knowledge on past populations. This approach also contributes to value the Belgian patrimony. More generally, new application areas could eventually emerge from such study. Based on adequate governance and methodologies, genetic results could be further structured into a large international and archeological database. New recent data visualization and interconnection techniques could be helpful to historical interpretations. They could bring innovative referential to mutually enrich local studies.