Overview
Haplogroup R-Y45 is a foundational early branch of the R-M73 cluster and likely arose among populations distributed along the Altai-Sayan ecological arc during the early Holocene. These groups lived in a mixed environment where forest, steppe and mountain resources converged, enabling adaptive subsistence strategies that combined upland hunting, extensive fishing, and intensive exploitation of river valleys. The early carriers of Y45 appear to have maintained stable demographic structures despite their mobility, resulting in a lineage with low but measurable internal differentiation. Archaeological parallels include composite hunting tools, elongated microlithic blades and bone implements typical of mobile Holocene cultures focused on mixed terrestrial and aquatic resources. Y45's phylogenetic position suggests it represents a lineage that branched off prior to the major demographic transformations associated with Bronze Age steppe pastoralism. Instead, it reflects a persistent forager tradition that remained integrated within the forest-steppe mosaic long after pastoralist migrations intensified. In the present day, R-Y45 is extremely rare and appears sporadically among individuals with ancestry in the Altai-Sayan region and in parts of northern Mongolia. Its rarity provides important insight into the demographic bottlenecks that affected early Holocene forager lineages and shows how small ancestral groups survived at the margins of later expansive cultural systems.