Overview
G2a9 is an uncommon but phylogenetically well-defined branch within the early–mid Holocene layer of G2a diversification. It appears to have formed in the corridor between the southern Caucasus and northwest Iran, a region associated with some of the earliest evidence of domesticated crops, structured settlements and intensive agro-pastoral economies.
G2a9’s limited diffusion suggests a lineage that remained tied to localized highland communities. Its internal microstructure points to multiple regional founder effects, likely reflecting small, semi-isolated populations during the Chalcolithic and Bronze Age periods.
Geographic distribution
G2a9 is found in Armenia, Azerbaijan, northern Iran and eastern Turkey at low frequencies. It occasionally appears in Iraq or Syria but remains rare overall. Its distribution aligns closely with zones of ancient cultural continuity around the Caucasus–Zagros interface.
Ancient DNA
- Several prehistoric Armenian Highland individuals show SNP patterns consistent with proto-G2a9.
- Possible upstream G2a9 signals occur in Chalcolithic samples from northwest Iran.
- No European ancient DNA belongs to G2a9, consistent with its purely West Asian trajectory.
Phylogeny & subclades
G2a9 forms several narrowly defined microclades with geographic clustering in the Armenian Highlands and northwest Iran. The structure indicates early divergence followed by long-term population stability. Its position on the G2a tree places it as a sibling radiation to other rare Near Eastern branches like G2a3–G2a8.
- G2a9* basal
- Armenian Highland subclades
- Azerbaijan–NW Iran branches
Notes & context
G2a9 enriches the representation of early West Asian paternal diversity within G2a and provides important context for understanding the demographic mosaic of early Holocene highland societies.
References & external links