Ancient-DNA study of 25 individuals from medieval and post-medieval Finland

We studied the ancestry, kinship, and health of individuals exhumed from three cemeteries in Finland: Tampere Vilusenharju and Pälkäne Ristiänmäki (11th–12th centuries), and Pälkäne Rauniokirkko (13th–early 19th century). The oldest burials provide rare insights into Finland's medieval population, which remains relatively unknown due to poor bone preservation. Our genetic analyses leveraged ancient genomic data, contemporary Finnish Biobank data, and identity-by-descent (IBD) analyses to reveal a high degree of regional continuity between the medieval and modern Finnish populations, as well as evidence for limited mobility within Finland and between Finland and Scandinavia. Kinship analysis identified a sibling relationship between individuals buried 30 km apart and indicated a shared genetic background for individuals from the three cemeteries. However, those buried in close proximity were not closely related, suggesting that burial practices emphasized social rather than genetic connections. Pathogen screening identified potential Yersinia and Treponema infections, offering a glimpse into the disease burden in medieval Finland.