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World War II and urbanization leave their mark on Finnish genetics

New analysis details how Finland's genetic makeup changed throughout the 20th Century


Research News


IMAGE: Ten reference groups used for decomposing genetic ancestry within Finland. view more 

Credit: Kerminen S, et al. (2021) PLOS Genetics

A team of researchers led by Matti Pirinen of the University of Finland used more than 18,000 Finnish samples to take an incredibly detailed look at how Finnish genetics have shifted, year by year, from the 1920s to the 1980s. They describe their results in a new paper published March 4th in PLOS Genetics.

Tens of millions of individuals have taken direct-to-consumer tests to find out their genetic ancestry profile. So far, these tests can only estimate ancestry on the scale of countries or continents, but Pirinen and colleagues wanted to take a more detailed look. They estimated the genetic ancestry of 18,463 Finnish individuals, tracking their genetics back to 10 distinct, original populations. Using this info, they looked at how the country's genetics changed each year between 1923 and 1987 in 12 geographical regions. The researchers observed major changes associated with World War II, when Finland lost parts of its eastern territories to the Soviet Union and 11% of the country's population was forced to move. Additionally, urbanization, starting in the 1950s, left its mark, as people moved into cities in the southern and western parts of the country.

This is the first time that scientists have estimated annual changes in the fine-scale ancestry profiles of individuals from a relatively homogeneous European country, and their work demonstrates that this information can capture a detailed history of a population in space and time. To make these results accessible to the public, the researchers have developed an interactive website, which enables interested users to browse an area's genetic ancestry at the municipal and region scale:


Peer-reviewed; Simulation / modelling

In your coverage please use this URL to provide access to the freely available article in PLOS Genetics:

Citation: Kerminen S, Cerioli N, Pacauskas D, Havulinna AS, Perola M, Jousilahti P, et al. (2021) Changes in the fine-scale genetic structure of Finland through the 20th century. PLoS Genet 17(3): e1009347.

Funding: This work was supported by the Academy of Finland ( (Grants 288509 and 319181 to M.Pi.), the Academy of Finland Center of Excellence in Complex Disease Genetics (312076 to M.Pi; 312062 to S.R.), by the Sigrid Juselius Foundation ( (to M.Pi and S.R.) by University of Helsinki ( HiLIFE Fellow and Grand Challenge grants (M.Pi. and S.R.), by the Finnish Foundation for Cardiovascular Research ( (S.R.) and by Professor Package A80202-921072-Vyas from Aalto University ( to R.V. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: V.S. has received honoraria from Novo Nordisk and Sanofi for consultations. He also has ongoing research collaboration with Bayer Ltd. (All unrelated to the present study).

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