Finnish DNA: haplogroup N, Siberian roots and the east–west line

One line out of thousands

A haplogroup is a branch of a family tree drawn from DNA that passes down a single line. The Y chromosome goes from father to son almost unchanged, so a Y haplogroup follows the paternal line back through the generations. Mitochondrial DNA goes from a mother to all her children, so a mitochondrial haplogroup follows the maternal line. Each traces one ancestor per generation, while the number of ancestors doubles with every generation back. Our short explainer covers the idea; this guide is about the Finnish branches.

The two trees are named separately, which causes one common mix-up. Haplogroup N on the Y tree and haplogroup N on the mitochondrial tree are unrelated lineages that happen to share a letter^{[4, 5]}. In this guide, N means the Y-chromosome lineage unless the text says otherwise.

The Finnish Y chromosome, counted from 1,802 sequences

Preussner and colleagues at the University of Helsinki used whole-genome sequences from the FINRISK population surveys: men born between 1923 and 1979, placed by their father's birthplace where it was known, so that the map shows Finland a generation further back^[1]. National figures are weighted by each region's population, because eastern Finland was oversampled.

The two large groups mirror each other on the map. N1a1 reaches 78 percent of men in North Karelia, North Savo and South Savo, and I1a reaches 53 percent in Central Ostrobothnia, on the west coast^[1]. R1a and R1b, about one man in ten between them, are lines the authors associate with eastern and western European ancestry.

N1c, N1a1, N3 and Tat are one lineage

An older forum thread, a recent paper and a test report can use four different names for the same branch. They are not competing claims. The Y tree is renamed as sequencing adds branches above and below a known one, and a label that encodes a position in the tree changes when the tree does. A name built from the defining marker, such as N-M46, does not depend on the tree's shape, and the 2025 Finnish study uses that style^[1].

Our report's label for a Finnish man on this line is haplogroup N, from the marker M231 at the top of the table. It does not yet read the markers below it, so it cannot say which Finnish branch a man carries.

Two routes into Finland

The study's main finding is that N1a1 in Finland is two branches with opposite geography. N-Z1934, carried by 42.2 percent of Finnish men, is most common in the east and reaches 69 percent of men in North Savo. N-VL29, carried by 22.2 percent, is most common in the south-west, where it makes up 64 percent of all N1a1 lines in Southwest Finland^[1].

The rest of the genome points the same way. Men on the south-western branch carried more south-western autosomal ancestry than men on the north-eastern one, even within one region, and compared with 32 Estonians, the Finnish region genetically closest to Estonia was Southwest Finland^[1]. N-VL29 is known as the Baltic branch of N1a1^[1], and it accounts for more than a third of the men in Estonia, Latvia and Lithuania^[2].

The authors say plainly what their data cannot do. Modern DNA cannot date when a branch arrived, and N-VL29 was already present in Viking-age Sweden, so a more complicated route cannot be ruled out^[1].

Where haplogroup N came from

Haplogroup N is one half of a pair. Its sister lineage, O, makes up the great majority of male lines in East and South-East Asia^[7]. Lines that branched off before N and O parted still survive at low frequency in continental South-East Asia, and the oldest branch of N is southern too: N4, which split off before the northern branches, is the main N lineage in Cambodia, Vietnam and China today^[2]. In 2007 Rootsi and colleagues proposed that N reached eastern Europe by a long counter-clockwise route from inner Asia and southern Siberia, roughly 12,000 to 14,000 years ago^[7].

Sequenced Y chromosomes put the later branching on a clock. Ilumäe and colleagues dated the split between N1a1, which they call N3, and its sister N2a to about 18,000 years ago. The split that matters for Finland came about 5,000 years ago, when one branch, N-L392, divided almost at once into regional lines that now run from the Baltic to Beringia^[2]. The ancient DNA they cite has N as the commonest paternal line in Neolithic north-east China, 6,500 years ago.

Those regional lines cut across language families. About half of the Y chromosomes of Lithuanians, Buryats and Chukchi, who speak Baltic, Mongolic and Chukotko-Kamchatkan languages, belong to the same N-L392 branch, and the authors describe this paternal affinity as decoupled from language^[2]. They link the timing to a mid-Holocene warming and to the Seima-Turbino metalworkers of 4,200 to 3,700 years ago, and call those parallels speculative.

What ancient DNA dates

Ancient genomes give dates that modern DNA cannot. The key site lies just outside Finland: Bolshoy Oleni Ostrov, a burial ground on the Kola Peninsula radiocarbon-dated to about 3,500 years ago^[3].

Lamnidis and colleagues conclude that migrations from Siberia began to shape the genetics of northern Europe at least 3,500 years ago, and that the later pattern reflects several episodes of mixing^[3]. Saag and colleagues place Siberian ancestry on the Estonian coast no later than the middle of the first millennium BC, in the same window in which linguists place the diversification of the Finnic languages^[6]. At Levänluhta, the Iron Age people of western Finland were related to today's Saami, whose languages were spoken across Finland before Finnish^[3].

The Y chromosome and the rest of the genome

The gap between the two measures shows most clearly in Estonia, where both have been published. More than 30 percent of Estonian men carry the N1a1 branch, while the Siberian-related share of the Estonian genome was estimated at 5 percent^[8]. Iron Age Estonians show the same pattern: half of a small sample of men carried N3a, while their genomes averaged 3 to 5 percent Siberian ancestry^[6]. Seven generations back, a family tree has 128 places, and the Y chromosome follows one of them.

Language lines up with neither measure. Hungarians speak a Uralic language but show no excess of Siberian-related ancestry, while Russians, who speak an Indo-European one, do^[3]. Latvians and Lithuanians, who speak Baltic languages, carry N1a1 about as often as Estonians^[8].

The maternal side looks different again. In Uralic-speaking populations the maternal lines largely match those of their neighbours, while eastern Y chromosomes are distinctly common in the European ones^[8]. A study of 843 complete Finnish mitochondrial genomes found haplogroup frequencies much like those of other Europeans, yet up to a third of the genomes fell in sub-branches common in Finland and rare elsewhere, the oldest, U5b1b2, almost 6,000 years old^[9]. East Eurasian maternal lines do occur: haplogroup Z, an Asian lineage, is among those Finns share with the Saami^[10].

The east–west line inside Finland

Finland's internal divide was found in the Y chromosome first. A 2006 study of 536 men described a sharp genetic border between eastern and western Finns, found no support for recent migrations from Siberia, and noted that the border had so far been seen only in Y-chromosome variation^[12]. Genome-wide data confirmed it two years later. The genetic distance between eastern and western Finland, an FST of 0.0032, was similar to that between subpopulations of Iceland and larger than the distance between the German and British samples in the same study, 0.0005^[13].

Settlement history explains much of it. The south-west and the coast were settled more densely and permanently from about 4,000 years ago; the interior north and east only from the 1500s, when settlers moving out of Savo founded new villages, each from a small number of people^{[11, 13, 14]}. In 43,254 Finns, Martin and colleagues found that people from the north-east share several times more of their genome in long identical segments than people from the south-west, and that growth began about 30 to 40 generations ago in the early-settled south-west against 15 to 25 in the late-settled interior^[11].

The 20th century blurred the line. During and after the Second World War more than 400,000 people, 11 percent of the population, left the eastern territories Finland ceded to the Soviet Union and were resettled across the country, and urbanisation from the 1950s mixed the regions further. Kerminen and colleagues could see both events in the genetic ancestry of people born year by year from the 1920s to the 1980s^[15]. That is why the Y-chromosome study placed men by their father's birthplace^[1].

Runs of homozygosity: a bottleneck inside one genome

Every genome has stretches where the two copies of a chromosome are identical, because both came down from one shared ancestor. Short runs are universal. In a study of European populations every person carried some runs shorter than 1.5 Mb, and runs of up to 4 Mb were common in people whose two sides of the family had no common ancestor for at least five generations^[16]. Length is the clue to age: long runs come from recent shared ancestors, the many short ones from shared ancestry tens and hundreds of generations back^[17], which is why runs can be read as population history^[18].

A population that grew from small founding groups carries more of them. Jakkula and colleagues found that runs longer than 1 Mb covered, on average, 0.9 percent of the genome in a south-coastal early-settlement sample and 2.0 percent in a north-eastern late-settlement isolate, and that up to 90 percent of people in the youngest subpopulations had at least one run longer than 5 Mb, against 9.5 percent of a US sample^[14]. Between people the same history shows as shared segments: two unrelated Finns share on average 107.0 cM of their genomes in identical stretches, two Swedes 22.9 cM^[11]. The same bottlenecks lie behind the Finnish Disease Heritage, the group of rare inherited conditions far more common in Finland than elsewhere^[11].

Our report measures this from a whole-genome VCF or gVCF. It splits the autosomes into 1 Mb bins, treats a bin as identical on both copies when it holds at least 50 variant calls of which at most 2 differ between the copies, joins neighbouring bins, and keeps runs of 3 Mb or more. The total, divided by the 2,875 Mb of autosome it counts, is F(ROH), the share of the genome in runs^[16]. A bin with too few variants counts as unmeasured, never as identical, so a thin file cannot pass off its gaps as runs.

What a DNA file can show

Different files reach these questions to different depths. This is what our report reads from each.

The paternal line stops at N. The report reads 13 Y-chromosome markers, M231 among them; M46 for N1a1 and the markers of N-Z1934 and N-VL29 are not on the panel yet. The maternal line goes much deeper: Haplogrep 3 places it on the full PhyloTree, Build 17.2, and names the branch even where we have written no paragraph about it^{[5, 21]}.

Chips need care with the Y. The 13 markers have no rsID and can only be found by position, and 23andMe and AncestryDNA exports number positions on the older GRCh37 assembly. The report translates each position from GRCh38 through a table checked against the surrounding sequence in both assemblies, and refuses exports that do not say which assembly they use. MyHeritage kits sold since October 2025 are sequenced, and their raw-data export has no Y chromosome at all^[20].

Runs of homozygosity need a whole genome. A chip types fixed positions and cannot tell an untyped stretch from an identical one, so the report does not measure runs on chips, and it also refuses exomes, low-pass genomes and any file with fewer than 300 variants per megabase. Nor does the ancestry composition put a Siberian percentage on anyone. Its Baltic Finnic reference group was built from present-day Estonian, Finnish, Karelian and Veps samples, so whatever eastern ancestry those populations share is already inside it, and a North Asia figure, where one appears, measures likeness to present-day Siberians, which is a different thing from the ancient contribution dated above. The free file check names a file's format and assembly in your browser before anything is uploaded.