Description

Haplogroup I2a (L460) is the major subclade of I2, split into two primary branches: I2a1 (M26), a Western European isolate concentrated in Sardinia, and I2a2 (M436), a widespread Western and Central European lineage. The broader I2a clade traces to Paleolithic European hunter-gatherers and its distribution reflects ancient genetic diversity that predates both Neolithic farming and Bronze Age steppe migrations. The 'Dinaric' branch of I2 — very common in South Slavic populations — is actually I2a1b under the modern classification, and represents a massive demographic expansion in the Balkan region.

Interesting Fact

The so-called 'Dinaric I2' (I2a1b-L621) — the most common Y-DNA haplogroup in Bosnia, Serbia, Croatia, and Ukraine — underwent an extraordinarily rapid population explosion approximately 1,000–1,500 years ago, coinciding with the Slavic expansion into the Balkans. This haplogroup went from rare to dominant across a huge area in just a few centuries, one of the fastest expansions recorded in European Y-DNA history.

Distribution by Ethnicity

Ethnic distributionRegionFrequencySample
BosniansSoutheast Europe
55%
n=300
SerbsSoutheast Europe
40%
n=400
SardiniansSouthern Europe (I2a1)
40%
n=400
CroatiansSoutheast Europe
38%
n=400
UkrainiansEastern Europe
22%
n=500

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References

  1. 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.