Tracing Finland’s founders: Genetic research uncovers new insights

In population genetic research, paternal lineages are classified into haplogroups, which are determined on by genetic variations found in Y chromosomes. This variation can be utilized in genetic genealogy, as well as in studying population history and migration routes.

In a study led by researchers from the University of Helsinki, the Finnish Y chromosomes have now been examined in significantly more detail than before. The results clarified the picture of the origins of the men who have migrated to Finland over the millennia.

- Our study utilized data from the THL's FINRISK study, which includes comprehensive Y chromosome genetic information of approximately 1800 Finnish men nationwide. The data enabled to study these haplogroups, or so-called paternal lineages, with an entirely new level of precision, says doctoral researcher Annina Preussner from the Institute of Molecular Medicine Finland (FIMM) at the University of Helsinki.

Southwest Finland has been reached from the south via the Baltics

Previous studies have shown that Y chromosomes of present-day Finns show both Western and Eastern influences, with most Finnish men belonging to either haplogroup N or haplogroup I. Traditionally, haplogroup I was thought to have come to Finland from the west and haplogroup N from the east.

Contrary to this established east-west division, the study found evidence that haplogroup N carriers may have migrated to Finland via multiple routes.

Haplogroup N divides into two sublineages, one of which is significantly more common in Southwest Finland shifting the prior understanding that the haplogroup N arrived solely from the east.

The haplogroup N subclade common in Southwest Finland seems to have arrived with men who migrated from the south, crossing the sea via the Baltics. One in three men in Southwest Finland belong to this group.

The dataset describes the situation in Finland from the early 1900s to around the 1950s, prior to the onset of large-scale internal migration and urbanization.

The origin of Finns is clarified through interdisciplinary research

The research team's results support linguistic and archaeological observations of the influence from the Baltic region in Southwest Finland. For example, the southwestern Finnish dialects share linguistic similarity specifically with the Estonian language.

In addition to the Y chromosome, the researchers examined the participants' overall genetic similarity to Estonian reference samples. The results supported the genetic similarity between southwestern Finns and Estonians.

- When examining genetic differences within Finland and between its regions and Estonia, we discovered that southwestern Finns are genetically as close to Estonians as they are to individuals from Kainuu in northeastern Finland, says Taru Tukiainen, an academy researcher leading the study from FIMM.

- Mapping the genetic origins of the population through such research is important, as it helps us deepen our understanding of the population's genetic diversity and its implications, for example, on regional health disparities.

According to Elina Salmela, who holds the title of docent in population genetics at the University of Helsinki, the results are interesting.

"The results show that the population history of Finns is more complex than seen in previous genetic studies," Salmela comments.

The results of the study have been published in the European Journal of Human Genetics.

In the study, it was possible to divide the previously described main haplogroups of Finland (N1a1, I1a, R1a, R1b) into numerous sublineages and thus identify paternal lineages that have not been previously reported among Finns. The results are freely accessible and can also be viewed on the website maintained by the research group.

Original publication:Y chromosome sequencing data suggest dual paths of haplogroup N1a1 into Finland. Annina Preussner, Jaakko Leinonen, Juha Riikonen, Matti Pirinen, Taru Tukiainen, Eur J Hum Genet. 2024 doi:10.1038/s41431-024-01707-7

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