Haplogroup I-M253 (I1)
I-M253 is the Nordic paternal lineage. Descended from Europe's ancient hunter-gatherers, it expanded from a single forefather and peaks in Sweden, Norway, Denmark and Finland. Explore the branch in the full Y-DNA haplotree: sub-branches, defining variants and where its testers live. Free, no account needed.
Paternal branch
Live tester counts
Free · no account needed
Paternal line
I-M253
- Testers
- 77,949
- 6,513 on this exact branch
- Strongest today
- Sweden, Norway, Denmark
- Formed
- Oldest man on this line
Origin and distribution of I-M253 (I1)
What is I-M253? It is haplogroup I1, Scandinavia's signature paternal line, descended from Europe's Ice Age hunter-gatherers but expanded from a single forefather only about 4,600 years ago.
- Its deep root
- Haplogroup I is genuinely ancient in Europe, the lineage of the continent's Ice Age hunter-gatherers.Source: Population genomics of post-glacial western Eurasia (2024)
- Its young expansion
- Nearly all living I1 men descend from one man who lived around 4,600 years ago, a bottleneck-and-boom of the kind that reshaped Y diversity across Eurasia.Source: A recent bottleneck of Y chromosome diversity coincides with a global change in culture (2015)
- Where it is common
- Roughly a third of men in Sweden, Norway and Denmark, common in Finland, Iceland, northern Germany and the Low Countries.
- Where it travelled
- The best represented father line in the Viking world study, found in most regions from Greenland to Russia. Many I1 lines probably reached the British Isles with the Vikings, and some earlier with the Anglo-Saxons.Source: Population genomics of the Viking world (2020)
I-M253, haplogroup I1, is Scandinavia's signature paternal line, carried by roughly a third of men in Sweden, Norway and Denmark and common across Finland, Iceland, northern Germany and the Low Countries. Its parent haplogroup I is genuinely ancient in Europe, the lineage of the continent's Ice Age hunter-gatherers, but nearly all living I1 men descend from one man who lived only around 4,600 years ago, a striking bottleneck-and-boom that ancient DNA places in the context of Nordic Bronze Age population growth.
The lineage travelled wherever Norse and Germanic populations went: Viking-era migrations carried I1 lines into Britain and Ireland (where they mark Danelaw and Norse settlement), Normandy, Iceland and the east-river routes into Russia. Its sub-branches are dense enough that many family lines can be told apart at the level of a few centuries.
One line among many: your Y haplogroup traces a single paternal line, one ancestor per generation out of thousands, so it is a thread of deep ancestry, not an ethnicity and not a percentage of who you are. Two men in the same branch share a forefather, but the rest of their genomes can differ as much as any two strangers'.
The line through time
Each branch on this line from the root of the tree, oldest first.
Where testers are found
Counts of people who took a Y-DNA test and shared an origin. They describe the tested world, not ancient frequencies.
Sweden
5,490 · 22%
England
4,277 · 17%
United States
3,518 · 14%
Germany
2,662 · 11%
Finland
2,522 · 9.9%
Norway
1,608 · 6.3%
Scotland
1,507 · 5.9%
United Kingdom
1,450 · 5.7%
Plus 48,197 testers who gave no country. Shares are of testers with a known country.
Where this branch runs strongest
The share of each country's testers who sit on this branch.
Sweden
1 in 2 · 45%
Norway
1 in 3 · 35%
Denmark
1 in 3 · 33%
What defines it
The changes on the Y chromosome that every man on this branch carries. Positions are on the GRCh38 reference.
Is this your line?
If you have tested with a consumer DNA company, your own branch is already in your raw data file. The free Clade Finder reads it and shows you where you sit on this tree.
Find my branch, freePrefer it read for you? The Ancient Ancestry report can carry your paternal haplogroup as an add-on, placed on this same tree beside your ancestry model.
Frequently asked questions
What is haplogroup I-M253 (I1)?
I-M253 is the Nordic paternal lineage. Descended from Europe's ancient hunter-gatherers, it expanded from a single forefather and peaks in Sweden, Norway, Denmark and Finland. It is a branch of the Y-DNA tree: everyone in it inherits the same set of defining mutations from one shared forefather.
How do I find out if I belong to I-M253 (I1)?
If you have already tested with a consumer DNA company, the free Y-DNA Clade Finder reads a raw DNA export (23andMe, AncestryDNA, MyHeritage or a VCF) and places you on the tree at the resolution your file supports. It is free, and the file is discarded after analysis. A dedicated Y-DNA sequencing test resolves deeper branches than a genotyping chip can.
Does belonging to I-M253 (I1) make me descend from one people?
No. A haplogroup follows a single paternal line, one ancestor per generation, while the rest of your ancestry doubles every generation back. It is a deep-time thread, not an ethnicity, and two members of the same branch can otherwise be as genetically different as any two strangers.
What does this page's tree data show?
The branch view on this page shows the branch inside the full Y-DNA haplotree of tested lineages: the line it descends from, the branches below it, the variants that define it, and the countries its testers report. Counts reflect people who have taken a Y-DNA test and shared an origin, so they describe the tested world, not ancient frequencies.
Keep exploring
Don't know your haplogroup yet? The free Y-DNA Clade Finder reads it from a raw DNA export. Or browse the whole tree in the Y-DNA Haplotree. Other major branches: