Overview
G-Z1903 is a major P303-derived branch with a dual Near Eastern–European profile. It is especially common in the Caucasus and persists across southeastern and central Europe. Unlike L497, which emphasizes central Europe, or L13, which marks western pathways, Z1903 uniquely connects the Caucasus–Anatolia–Balkans corridor with later expansions north and west into Europe.
Its structure reveals a deep split between Caucasus-centered lineages and European-centered radiations. The Caucasian branches are older and more internally diverse, indicating long-term continuity in highland zones. The European branches represent Neolithic and post-Neolithic expansions that extended into the Balkans, Carpathian Basin and central Europe.
Geographic distribution
Z1903 reaches its strongest frequencies in the Caucasus (Georgia, Armenia, Dagestan), eastern Anatolia and the northern Fertile Crescent. In Europe, Z1903 appears across the Balkans, Romania, Hungary, Poland, Germany and occasionally the Alps. Some modern Italian and Iberian individuals also belong to downstream Z1903 branches.
Its wide but structured range mirrors both early Near Eastern farming expansions and later interactions across the Caucasus–Balkan interface. The lineage is relatively rare in western Europe but shows pockets signalling ancient migration routes.
Ancient DNA
- Chalcolithic and Bronze Age individuals from the Caucasus and eastern Anatolia display Z1903-related markers, confirming its deep Near Eastern and Caucasus presence.
- A minority of Early Neolithic Balkan individuals carry P303 lineages potentially ancestral to Z1903.
- Later Neolithic and Copper Age individuals in central and eastern Europe show branches consistent with Z1903 expansions into the Carpathian Basin.
- Several Bronze Age individuals on both sides of the Caucasus display Z1903 subclades, reinforcing its long-term regional continuity.
Phylogeny & subclades
Z1903 splits into two major radiations: Caucasus-centered branches and European-centered branches. Caucasian subclades include deep and highly diverse lines, while European variants tend to form shallower clusters reflecting Neolithic and later expansions.
Downstream WGS analysis reveals multiple microclades with clear regional signatures, including branches restricted to Georgia, Armenia, the Balkans or central Europe.
- Z1903* basal lineages
- Caucasus-centered Z1903 branches
- European Z1903 branches (Carpathian, Balkan, central European clusters)
- Microclades identified through whole-genome sequencing
Notes & context
Z1903 is crucial for understanding connectivity between the Caucasus and Europe. Its dual structure shows that early Neolithic expansions were not purely westward from Anatolia; rather, they involved complex bidirectional interactions between highland regions of the Caucasus and early European farmer groups. In population history reconstructions, Z1903 helps distinguish between Anatolian–Aegean pathways and Caucasus–Balkan interaction zones.
References & external links