Haplogroup I1 (Y-DNA) is the original paternal lineage of Nordic Europe. In human genetics, Haplogroup I-M253 is a Y chromosome haplogroup which occurs at greatest frequency in Fenno-Scandia. The mutations identified with Haplogroup I-M253 (Y-DNA) are M253, M307, P30, and P40. These are known as single nucleotide polymorphisms (SNPs). It is a subclade of Haplogroup I.
Haplogroup I-M253 arose from haplogroup I-M170, which appears ancient in Europe. The haplogroup was previously thought to have originated 15,000 years old in Iberia, but is now estimated to have originated between 4,000 – 5,000 years ago. It is suggested that it initially dispersed from Denmark.
I-M253 is found at its highest density in Northern Europe and other countries that experienced extensive migration from Northern Europe, either in the Migration Period, the Viking period or modern times. It is found in all places invaded by the ancient Germanic peoples and the Vikings. In the modern era, significant I-M253 populations have also taken root in immigrant nations and former European colonies such as United States, Australia and Canada.