Overview
G2a3 is a relatively newly resolved upstream branch of G2a, detected almost exclusively via high-coverage whole-genome sequencing of Near Eastern individuals. It predates the major Neolithic-associated G2a2 radiations but sits younger than the oldest basal G2a branches. This makes G2a3 a key lineage for understanding the early internal diversification of the G2a trunk prior to its massive Neolithic expansion.
Although extremely rare today, G2a3 represents the type of small, regionally confined paternal line that likely characterized early Holocene highland and foothill populations in Anatolia, northern Mesopotamia and the Caucasus fringes.
Geographic distribution
G2a3 has been detected in extremely low frequencies in eastern Anatolia, Armenia, Azerbaijan and northern Iraq. These regions form the deep-time G2a diversity center. No confirmed modern European cases exist, consistent with its lack of participation in the Neolithic expansions dominated by G2a2.
Occasional South Caucasus and western Iranian individuals sit near the G2a3 stem, likely representing ancient continuity.
Ancient DNA
- A small number of upstream G2a individuals in Pre-Pottery Neolithic northern Mesopotamia show affinity to proto-G2a3.
- Possible early Holocene Caucasus highland genomes exhibit markers compatible with ancestral forms of G2a3.
- No known European Neolithic remains fall under G2a3 or its immediate derivatives.
Phylogeny & subclades
G2a3 remains sparsely sampled, with a handful of basal sublineages forming shallow clusters. Its position within G2a phylogeny provides key resolution for the early branching order of the G2a tree. It appears to form one of the ‘lost’ radiations that did not participate significantly in later major human migrations.
- G2a3* basal
- Anatolia–Caucasus microclades
Notes & context
G2a3 is a crucial addition for reconstructing the deep structure of G2a. It helps account for ancestral Near Eastern paternal variation that did not contribute to Europe’s Neolithic but shaped early West Asian population networks.
References & external links