Overview
Haplogroup R-Y31 is a key early Holocene branch under the R-M73 lineage and provides an important window into the deep prehistoric population structure of Inner Asia. Its formation during the post-glacial interval aligns with the major ecological reorganization of northern Eurasia when climatic warming opened new ecological niches in the Minusinsk Basin, the Altai foothills and the western Sayan region. The Y31 lineage likely developed within small hunter-fisher groups that were expanding northward and eastward as forest and forest-steppe biomes stabilized. The phylogeny of R-Y31 indicates an early split followed by long-term regional isolation among small forager communities. Y31 appears to have persisted through the Neolithic with minimal external gene flow, suggesting a stable demographic structure dominated by localized kin groups. Archaeological evidence from the early Holocene in the Sayan and Upper Yenisei region shows continuity between Mesolithic and early Neolithic groups, and this cultural stability aligns well with the genetic continuity suggested by the Y31 branch. Today, R-Y31 is rare but occurs in trace levels across the Altai-Sayan macroregion, southern Siberia, and portions of northern Mongolia. Its distribution corresponds closely to areas known for long-term forager settlements and relatively late adoption of pastoralism. The persistence of Y31 highlights a deep-time demographic layer beneath later expansions of Indo-European, Turkic and Uralic-speaking populations.