Overview
Haplogroup R-P241 represents an early internal branch of R1 that predates the divergence of R1a and R1b but immediately follows the upstream node R-P245. This lineage belongs to a phase of Upper Paleolithic genetic structuring that took place across northern Eurasia as human populations adapted to cold steppe and forest steppe environments during the Last Glacial Maximum. R-P241 is thus part of a deep paternal layer that sets the foundation for all later expansions of R1 lineages. Although rarely detected directly in present day individuals, R-P241 is critical for reconstructing the earliest stages of R1 diversification. The structure of downstream branches indicates that early carriers of R-P241 were likely distributed across parts of southern Siberia, Kazakhstan and adjacent steppe regions. These groups later contributed ancestry to populations associated with the Mesolithic hunter gatherers of Eastern Europe and eventually to the major Bronze Age expansions of R1a and R1b. R-P241 is a genetic ghost branch in the sense that its full diversity has been obscured by the overwhelming expansions of its descendants. Yet its placement is essential for forming a complete and accurate phylogenetic scaffold for haplogroup R1.