A new genetic study has revealed that early medieval Finland was inhabited by separate and differing populations, all of them influencing the gene pool of modern Finns. The study is so far the most extensive investigation of the ancient DNA of people inhabiting the region of Finland.
In the study, cried out by researchers from the University of Helsinki and the University of Turku, genes were investigated from archaeological bone samples of more than one hundred individuals who lived between the 4th and 19th centuries AD. Most of the samples originated in the Iron Age (approximately 300-1300 AD) and the medieval period (approximately 1200-1500 AD). Mitochondrial DNA (mtDNA), which is passed down by mothers to all of their offspring, was extracted from the individuals, thus uncovering the population history of women.
Based on the findings, the people who inhabited Finland in the Iron Age and the Middle Ages shared mitochondrial lineages with today’s Finns. However, significant differences were seen in the genome of individuals buried in different burial sites in the Iron Age in particular. mtDNA lineages typical of Stone Age hunter-gatherers were common among those buried in Luistari, Eura (southwest Finland), and Kirkkailanmaki, Hollola (southern Finland). In Kylalahti, Hiitola (Republic of Karelia, Russia) and Tuukkala, Mikkeli (eastern Finland), the most common findings were lineages characteristic of ancient European farmer populations. The fifth Iron Age burial site included in the study is located in Levanluhta, western Finland. Many of the individuals buried there represented mtDNA lineages associated with the modern Sami.
“All of the above originally independent lineages remain common in Finland to this day. This indicates that the studied Iron Age populations have had an impact on the gene pool of contemporary Finns,” says doctoral student Sanni Oversti from the Faculty of Biological and Environmental Sciences, University of Helsinki, Finland.
The article adds that:
Within Finland, an unusually strong genetic border bisects the population along a northwest to southeast axis, and is interpreted to reflect an ancient boundary between hunter-gatherer and farmer populations. The expanse of agriculture north-east of this border was probably limited by environmental factors, especially the length of the growing season. Later, this border has most likely acted in demarcating the spread of western and eastern political and cultural impacts influencing the placement of first political border between Sweden and Novgorod through the middle of Finland (Treaty of Noteborg 1323 AD).
The researchers posit that the differences found in the Iron Age populations of western and eastern Finland are opposite to those found in today’s Finns: the lineages associated with ancient farmers were more common in the east, while the lineages inherited from hunter-gatherers were more prevalent in the west. Farmer populations arriving in Finland not only from the west and south but also from the east provides a potential explanation for this.
The article, “Human mitochondrial DNA lineages in Iron-Age Fennoscandia suggest incipient admixture and eastern introduction of farming-related maternal ancestry,” by Sanni Översti et al., is published in Scientific Reports. Click here to read it.
Top Image: Medieval burial site of Kalmistomäki in Kylälahti, Hiitola in Russia. Photo by Stanislav Belskiy