Overview
I2a2a2 (PF3855) represents one of the foundational branches of the I2-M223 (I2a2a) radiation and is strongly associated with the early Neolithic and Chalcolithic populations of continental Europe. Emerging in the wake of the interaction between indigenous Mesolithic foragers and incoming early farmers, this clade embodies the deep genetic imprint of western and central European cultural transformations around the Danube corridor. Its demographic signature suggests stable integration into Neolithic communities rather than rapid expansion.
Geographic distribution
Today, I2a2a2 is found at modest frequencies in Germany, the Czech Republic, Austria, Switzerland, eastern France and Poland. Its presence in the British Isles appears at low levels, likely linked to Early Bronze Age and Bell Beaker–associated contacts. Small but stable frequencies in Scandinavia indicate ancient continental influx rather than local origin.
Ancient DNA
- Multiple Early Neolithic remains from the Danube and Rhine basins exhibit upstream I2a2 genetic structure ancestral to PF3855.
- Bell Beaker-associated individuals occasionally carry PF3855-related lineages, revealing assimilation into pan-European exchange networks.
- Chalcolithic genomes from southern Germany and Alsace indicate the presence of early PF3855 substructure in farming contexts.
Phylogeny & subclades
I2a2a2 is the sister lineage to I2a2a1 (M284) within the I2a2a branch. SNP PF3855 differentiates an early continental cluster from the insular-dominant M284 branch. Downstream diversification is limited but regionally patterned, with markers such as L701 and CTS10057 defining recognizable sublineages.
- I2-L701
- I2-CTS10057
- Basal PF3855* clades
Notes & context
I2a2a2 is essential for understanding the genetic legacy of Mesolithic–Neolithic interactions in central Europe and the role of local paternal lineages in early European farming societies.
References & external links