On 18 August at 10:15, Stefania Sasso will defend her doctoral thesis “Population dynamics and health in medieval Europe: an archaeogenomic perspective“'.
Supervisors:
Professor Kristiina Tambets, University of Tartu
Professor Toomas Kivisild, KU Leuven (Belgium) and University of Tartu
Oponent:
Wolfgang Haak, Max Planck Institute of Evolutionary Anthropology (Germany)
Summary
The thesis focuses on the medieval period in Belgium and Estonia, from the perspective of ancient DNA analysis, to reconstruct population dynamics over time. The Middle Ages were not uniform but developed differently across Europe. Conventionally, in Central Europe, it began with the fall of the Western Roman Empire. Shortly thereafter, the Merovingian Kingdom emerged in the territory of present‑day Belgium, which forms the focus of the first study included in this thesis. Ancient DNA analyses revealed that the North Sea coastal community in Koksijde was not genetically homogeneous but comprised two main ancestry components: a predominant component closely related to medieval populations from England, and a less frequent component related to earlier Gaulish groups.
The thesis then investigates population structure at the inland Belgium site of Sint‑Truiden, which developed as a pilgrimage centre around the abbey founded by Saint Trudo. Its long temporal span of more than one millennium reveals a shift from an initially heterogeneous population towards greater homogeneity and increasing similarity to modern regional populations.
Christianity spread widely across Europe, including Estonia, where it was introduced following the Northern Crusades in the 13th century. This event marks the beginning of the medieval period in Estonia and coincides with major changes in population structure. Ancient DNA analyses reveal that medieval Estonian cities were considerably more heterogeneous, comprising both local individuals and people of Central‑Western European origin who belonged to different social classes, whereas rural settlements were predominantly inhabited by local populations.
Finally, to investigate the health status of individuals included in the previous studies, this thesis focuses on human betaherpesviruses 6A and 6B. For the first time, these viruses were identified in ancient human remains, allowing the reconstruction of their phylogenetic history. The results show that both viruses were already circulating in Europe from at least the Iron Age. Moreover, this study demonstrates that, with sufficiently big datasets, it is possible to trace the long‑term evolutionary history of human pathogens.
The defence can also be followed via Zoom.
https://ut-ee.zoom.us/j/95525479867?pwd=gQgW7Wcoab86mi1eavsJFxEY7z8HLG.1
Meeting ID: 955 2547 9867
Passcode: 093574
