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Y-DNA Haplogroup Atlas

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Haplogroup I2a2

I2a2-M436

Macro-haplogroup
I
Parent clade
I2
Formed (estimate)
c. 18,000–22,000 years before present
TMRCA (estimate)
c. 10,000–13,000 years before present

Overview

I2a2 represents the major western and central European oriented branch of haplogroup I2 and is one of the most important paternal lineages of the western Mesolithic. It has been identified in numerous ancient individuals from France, Germany, the Low Countries and the British Isles, as well as in parts of Scandinavia during the early Holocene. I2a2 reflects the demographic structure of western European hunter gatherers before the arrival of agriculture. Its lineages declined in frequency after the Neolithic transition, but many survived as minority components integrated into early farming societies. I2a2 branches also appear in early medieval populations of central and western Europe, showing long term continuity despite demographic changes associated with the Bronze Age and Iron Age.

Geographic distribution

Modern frequencies of I2a2 are highest in Germany, the Netherlands, Denmark and parts of France and Britain. It also occurs in Poland, Czechia and Switzerland at moderate levels, reflecting ancient European ancestry overlaid by later expansions of R1b, I1 and other lineages. Outside Europe, I2a2 is rare and mainly found in diaspora populations.

Ancient DNA

  • Mesolithic individuals from Germany, France and the Low Countries frequently belong to I2a2 variants.
  • British and Irish Mesolithic samples include I2a2 derived lineages, making it one of the earliest paternal markers of the British Isles.
  • Early Neolithic individuals in central Europe retain I2a2 as a minority lineage, reflecting continuity with earlier foragers.
  • Early medieval remains in northwest Europe include I2a2 subclades that survived the Bronze and Iron Age transitions.

Phylogeny & subclades

I2a2 divides into several important subbranches often labeled as I2a2a, I2a2b and additional microclades. These reflect regional founder effects in the Rhine basin, the North Sea region, and western and central Europe. The structure complements the southeastern European focus of I2a1.

  • I2a2a – Rhine and North Sea clusters
  • I2a2b – central European microbranches
  • additional I2a2 regional clades

Notes & context

I2a2 is indispensable for understanding the paternal ancestry of western European hunter gatherers. Its early presence in France, Germany, the Low Countries and the British Isles makes it one of the cornerstones of pre Neolithic paternal history.