Overview
I3a represents the Anatolia–Caucasus oriented branch of the I3 lineage. It likely formed during the terminal Upper Paleolithic or early Holocene within a population network spanning eastern Anatolia, Armenia and western Georgia. These communities experienced climatic fluctuations, localized refugia dynamics and early postglacial expansions, which shaped the distinct phylogenetic profile of I3a.
The lineage is thought to have interacted extensively with CHG-related groups and early pre-Neolithic Anatolian populations. However, unlike the later dominant lineages seen in the Neolithic and Bronze Age, I3a persisted only as a minor component. Its presence in modern populations remains a faint echo of a Paleolithic demographic layer that was gradually overshadowed.
Geographic distribution
I3a today is found primarily in Armenia, eastern Turkey and the Caucasus foothills. Rare individuals appear in Iran and Azerbaijan. Occasional cases in southeastern Europe likely trace to ancient movements from Anatolia or the Caucasus.
Outside these regions, I3a is essentially absent.
Ancient DNA
- CHG-related genomes often include unassigned basal I variants, some of which may originate from near the I3a stem.
- Pre-pottery Neolithic samples from Anatolia exhibit minor paternal diversity consistent with rare I3-like origins.
- Early Holocene forager groups in the Armenian Highlands likely harbored I3a lineages.
Phylogeny & subclades
I3a is a shallow but distinct branch of I3, containing several microvariants that reflect long-term low-level survival. Due to extremely small population sizes historically, its internal divergence is limited but still identifiable.
- I3a1 – Armenian Highland microbranch
- I3a2 – eastern Anatolian piedmont lineage
Notes & context
I3a is a genetic fossil of early postglacial Anatolia and Caucasus ancestry. While rare, it fills a crucial gap in the Paleolithic paternal narrative.
References & external links