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Y-DNA Haplogroup Atlas

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Haplogroup G2b2a

G-CTS6841

Macro-haplogroup
G
Parent clade
G2b2
Formed (estimate)
c. 10,000–12,000 years before present
TMRCA (estimate)
c. 5,000–7,000 years ago

Overview

G2b2a is a significant early branch within the G2b2 lineage, displaying a distribution centered on the northern Fertile Crescent, eastern Anatolia, and the South Caucasus. It appears to have formed during the late Neolithic or early Chalcolithic period, possibly within the cultural nexus linking the Upper Euphrates, the Armenian Highlands, and northwest Iran. Unlike G2b1b’s recent founder event, G2b2a reflects an older and more stable demographic history with moderate geographic diffusion across West Asia. Its presence in both highland and lowland archaeological regions suggests involvement in Bronze Age cultural networks and trans-regional interactions.

Geographic distribution

Modern representatives are found in eastern Anatolia, Armenia, Georgia, Iran, and northern Mesopotamia. Low-frequency traces appear in Central Asia—possibly related to Bronze Age population movements along the southern Caspian corridor. The lineage is rare in Europe, suggesting limited participation in the Neolithic dispersals that carried G2a lineages westward.

Ancient DNA

  • Probable G2b2a-related signals appear in Chalcolithic and early Bronze Age Armenian highland individuals, though full assignments await better Y-chromosome coverage.
  • A subset of Tell Brak (northern Mesopotamia) Bronze Age males show haplotypes close to G2b2-associated variation.
  • Genomic affinity patterns point to a deep-rooted Near Eastern origin consistent with early highland agricultural societies.

Phylogeny & subclades

G2b2a forms the primary known sub-branch of G2b2, defined by CTS6841 and several associated markers. Its internal branching is moderate, including several micro-regional clusters in Armenia and Iran. Phylogenetically, it stands parallel to the G2b1 complex and represents a more conservative, less drift-affected lineage within the G radiation.

  • G2b2a* (basal)
  • G2b2a1 (Z8077-linked cluster)
  • Additional private Armenian/Iranian micro-branches

Notes & context

G2b2a sheds light on the demographic structure of early agropastoral societies in the northern Fertile Crescent. Its continuity across the Armenian Highlands and Iranian plateau aligns with archaeological evidence for long-term cultural and genetic interaction across these regions. The lineage offers contrast to the more drift-dominated branches of G2b and helps better contextualize the ancestral diversity of the G2b complex.