Overview
J2c-M137 represents one of the rarest and deepest branches of the J2-M172 lineage, standing as a phylogenetic sibling to the major J2a agricultural expansion and the Balkan–Aegean oriented J2b radiation. Forming in the Upper Paleolithic or earliest Holocene, J2c preserves an ancestral demographic layer associated with early highland forager-herder communities of western Iran, northern Mesopotamia, and the Zagros corridor. Unlike J2a, which became a dominant paternal lineage of Neolithic agriculturalists across West Eurasia, J2c did not participate in major agricultural expansions. Instead, it retained a small, fragmented demographic footprint, surviving in mountainous refugia that historically resisted large-scale demographic turnover. J2c's significance lies not in its frequency but in its deep phylogenetic position, which helps reconstruct the earliest diversification of the entire J2-M172 clade.
Geographic distribution
Today, J2c is scattered in extremely low frequencies across western Iran, the central Zagros, eastern Anatolia, northern Iraq, the southern Caucasus, and parts of Levant. Rare signals in Pakistan, Afghanistan, and north India indicate ancient diffusion routes along early Iranian Plateau–South Asia cultural corridors. Sporadic occurrences in the Mediterranean (Crete, Sicily, Cyprus) likely reflect early maritime contacts involving small J2c lineages. The distribution pattern strongly suggests that J2c survived primarily in upland communities where geographic isolation limited gene flow with larger expanding lineages such as J2a, R1b, and later Iranian-related HGs.
Ancient DNA
- Neolithic Zagros aDNA (Ganj Dareh) includes upstream J2 signals potentially ancestral to J2c.
- Early Chalcolithic individuals from Seh Gabi and Tepe Abdul Hosein show rare J2-M172* signatures compatible with ancient J2c-like divergence.
- Upper Tigris/Euphrates Chalcolithic populations demonstrate paternal structure that may include archaic J2c remnants.
- No confirmed direct J2c ancient samples yet, but several J2-M172* highland individuals fall phylogenetically closer to M137 than to J2a/J2b splits.
Phylogeny & subclades
J2c-M137 forms the third basal branch of J2-M172 beside J2a and J2b. It diverged before the major Neolithic expansions and retains several primitive variants. Deep splits within J2c remain poorly resolved due to extremely limited sampling, but the lineage forms a key calibration point in reconstructing J2’s early branching tree. Its molecular clock estimates place it at a crucial period in early Holocene demographic restructuring across the Iranian Plateau.
- J2c* basal
- Highland Zagros paragroup lines
- Minor Caucasus-linked derivatives
Notes & context
J2c’s extreme rarity today is misleading in terms of its evolutionary importance. As one of the earliest J2 divergences, it is essential for reconstructing the deep phylogenetic history of West Asian paternal lineages and for contextualizing the ancestry of Neolithic Iranian Plateau populations.
References & external links