Description
Haplogroup I1a (DF29) is the dominant subclade of I1 and the primary Scandinavian Y-DNA lineage, representing the majority of I1 carriers in Northern and Western Europe. DF29 is essentially the 'crown group' of I1, containing almost all modern I1 diversity. It is most common in Sweden, Norway, Denmark, Finland, and Iceland, where it can reach frequencies of 30–40%. I1a expanded dramatically during the Viking Age (800–1100 CE) and its associated population movements, spreading Norse-derived I1a lineages across the British Isles, Normandy, Russia, and even Iceland and Greenland.
Interesting Fact
I1a (DF29) underwent a remarkable population expansion approximately 2,500–4,000 years ago that geneticists call a 'star-like radiation' — the haplogroup exploded from a small founder population into dozens of sub-branches within a few centuries. This rapid expansion is consistent with the rise of Bronze Age Norse cultures in Scandinavia and the selective advantages they conferred.
Distribution by Ethnicity
| Ethnic distribution | Region | Frequency | Sample |
|---|---|---|---|
| Icelanders | Northern Europe | n=300 | |
| Swedes | Northern Europe | n=600 | |
| Norwegians | Northern Europe | n=500 | |
| Danes | Northern Europe | n=400 | |
| British / English | Northwestern Europe | n=800 |
Tags
References
- Rootsi et al. (2004) — Phylogeography of Y-chromosome haplogroup I reveals distinct domains of prehistoric gene flow in europe. American Journal of Human Genetics 75(1), 128–137.