Overview
Haplogroup R-Y138750 is a rare but phylogenetically meaningful branch of R2a that appears to have formed in the wider Zagros and southern Caucasus sphere. Its estimated formation during the middle Holocene coincides with the maturation of early farming communities in the highlands of western Iran and adjacent Transcaucasian regions. These communities played a key role in mediating cultural and genetic exchange between Anatolia, Mesopotamia, the Iranian Plateau and the steppe margins to the north. Today, Y138750 is encountered mainly in western Iran, Armenia and eastern Turkey, with occasional occurrences in neighboring Caucasian populations. This distribution suggests that the lineage arose among highland groups associated with early agricultural and mixed agro-pastoral lifeways that later fed into the cultural trajectories of the Kura Araxes and related archaeological complexes. The confinement of Y138750 to this mountainous arc reflects the stabilizing effect of rugged terrain on the preservation of older paternal lineages. Although ancient DNA samples directly assigned to Y138750 have not yet been reported, several R2a positive individuals from Chalcolithic and Bronze Age contexts in the Armenian Highlands and western Iran provide strong circumstantial support for the antiquity of this branch in the region. The age and geography of Y138750 make it particularly relevant for reconstructing how R2a contributed to the paternal ancestry of early highland Near Eastern populations.