Brief
Study links Swedish migration to genetic split between Finland’s coast and interior
Ancient DNA analysis reveals that coastal Finns now carry more Scandinavian ancestry than their inland counterparts.
By Felo News Desk · Published
Researchers at the University of Turku have traced a genetic divergence between Finland’s southwestern coast and its inland regions, showing that migration from Sweden reshaped the coastal gene pool while inland populations retained continuity with medieval ancestors, according to a study published in Genome Biology on Oct. 6.
What happened
The team analysed 34 ancient genomes – 32 from individuals dated to the 11th‑13th centuries and two from the Late Iron Age – and compared them with modern Finnish DNA and ancient samples from across the Baltic Sea. During the early medieval period (1050‑1250 CE) coastal and inland groups were genetically similar despite cultural differences. Over subsequent centuries, inland areas such as Häme showed near‑continuous ancestry, while the coast acquired a substantial Scandinavian component.
What the reports add
Lead author Ronan James O’Sullivan said the findings suggest large‑scale Swedish migration began after the early medieval era, even though smaller movements occurred earlier. The study also mapped shared DNA segments across the Baltic, indicating long‑distance familial links that complement archaeological and historical evidence.
What was said
"Our findings suggest that migration from Sweden began to have a broader impact on Finland’s population relatively late, during the Middle Ages," O’Sullivan told Scitechdaily.
How it came about
The research builds on earlier work highlighted by Felo News on ancient DNA techniques, linking past population shifts to modern genetic landscapes.
Key facts
- Coastal Finns now have considerably more Scandinavian ancestry than inland Finns. (scitechdaily.com)
- The study examined 34 ancient genomes, including 32 from the 11th‑13th centuries. (scitechdaily.com)
- Inland regions like Häme show near‑continuous genetic ancestry for almost a millennium. (scitechdaily.com)
Sources
- [1] scitechdaily.com — originally reported as “The 1,000-Year DNA Mystery: Why Finland’s Coast and Inland Are Now Genetically Divided”
