Overview
G2a2b2a (P303) is the largest and most widespread expansion within the G2a2b (L30/S126) lineage, and one of the pivotal Y-chromosome clades associated with the European Neolithic. Defined by the P303 mutation, this lineage represents a massive demographic expansion that began in the Near East and radiated outward during the early to middle phases of the Neolithic. Its distribution today forms a connective thread across the Balkans, central Europe, the Caucasus, Anatolia and the Mediterranean, mirroring archaeological evidence of Neolithic diffusion from the Aegean and Anatolian core regions.
The internal substructure of G2a2b2a reveals that early Neolithic populations carried several distinct P303-derived lines as they moved into Europe along both the continental (Balkans → Danube) and maritime (Aegean → Adriatic → Mediterranean) routes. Many European regions still retain geographically specific derivatives of P303, illustrating localized founder effects and long-term continuity of early farming communities.
Geographic distribution
P303 shows considerable diversity across the Near East, Caucasus, Anatolia and southeastern Europe. The oldest basal forms occur in these regions, especially around the northern Fertile Crescent and the southern Caucasus. In Europe, P303 subclades appear throughout central Europe, the Alps, the Balkans, Italy, France, the Iberian Peninsula and the Mediterranean islands.
Regional concentrations include the Alps (especially Tyrol and Switzerland), northern Italy, parts of the Balkans, Sardinia and southwestern France. Mediterranean islands often harbor old P303 derivatives linked to early maritime Neolithic movements. Pockets of G-P303 diversity also persist in the Caucasus and the Levant, where Near Eastern farmer lineages maintained deep continuity.
Ancient DNA
- Numerous LBK (Linearbandkeramik) individuals belong to P303-derived clades, marking P303 as one of the principal paternal lines of early central European farmers.
- Multiple Early Neolithic Balkan individuals exhibit P303, aligning with the earliest Aegean-Neolithic movements into southeast Europe.
- Middle Neolithic and Copper Age individuals from France, Iberia and the western Mediterranean show P303 subclades, consistent with maritime Neolithic dispersals.
- Several Neolithic and Chalcolithic individuals from Anatolia and the Caucasus carry basal or early-diverging P303 lineages.
- Ötzi’s broad phylogenetic placement within G2a2b2a supports the deep antiquity of P303 in the Alpine region.
Phylogeny & subclades
G2a2b2a is the trunk for multiple major downstream expansions. Its phylogeny includes several high-resolution clusters that correspond to discrete European and Near Eastern founder events. The main branches include L497, U1, L13, Z1903 and smaller derivatives tracing region-specific Neolithic and post-Neolithic expansions.
The internal topology suggests an early split between Near Eastern–Caucasus-centered branches and European-centered lineages, followed by repeated waves of founder events in Europe and the Mediterranean.
- G2a2b2a1 (various basal P303 sub-branches)
- G-L497 (major European expansion lineage)
- G-U1 (Near East / Europe spanning clade)
- G-L13 (western and central European concentration)
- G-Z1903 (Caucasus / Europe interface branch)
Notes & context
P303 is the core lineage for reconstructing the demographic history of Europe’s first farmers. Its distribution and internal phylogeny align tightly with archaeological data on Neolithic migration routes and regional founder effects. For the atlas, P303 acts as the key structural node connecting Anatolian farmer ancestry with its later continental dispersals.
References & external links