Haplogroup I1 (Y-DNA)

In human genetics, Haplogroup I1 is a Y chromosome haplogroup occurring at greatest frequency in Scandinavia, associated with the mutations identified as M253, M307, P30, and P40. These are known as single nucleotide polymorphisms (SNPs). It is a subclade of Haplogroup I. Before a reclassification in 2008,[1] the group was known as Haplogroup I1a.[2] Some individuals and organizations continue to use the I1a designation.

The group displays a very clear frequency gradient, with a peak of approximately 40 percent among the populations of western Finland and more than 50 percent in the province of Satakunta,[3] around 35 percent in southern Norway, southwestern Sweden especially on the island of Gotland, and Denmark, with rapidly decreasing frequencies toward the edges of the historically Germanic sphere of influence.

For several years the prevailing theory was that during the Last Glacial Maximum (LGM) the predecessors of the I1 group sought refuge in the Balkans.[4] For a time, the Ukraine was considered as an alternative. Yet, The Genographic Project claims that the founder of the I1 branch lived on the Iberian Peninsula during the LGM. Some have given southern France and the Italian peninsula as possible sites as well.[5] Although the locations vary, proponents of the refuge theories do seem to agree on one issue: that the I1 subclade is from 15,000 to 20,000 years old.[6]