Overview
Haplogroup R-PF6500 is an extremely rare upstream branch of haplogroup R that diverged shortly after the formation of R-M207 and before the better known V45, R1 and R2 lineages. PF6500 represents a deep structural element of the R macro haplogroup and provides crucial resolution for early Eurasian paternal diversification during the terminal Pleistocene. PF6500 likely arose in a population of highly mobile foragers inhabiting parts of Central Asia or the southern Siberian steppe. Climatic instability during this period resulted in repeated population shifts, founder effects and localized extinctions. The scarcity of PF6500 in modern and ancient datasets suggests that this lineage existed in small demographic groups that did not participate in later large scale expansions during the Holocene. Although rarely detected directly, PF6500 remains essential for reconstructing the mutation pathway leading from R-M207 to its main descendant branches. These early ghost lineages demonstrate that early haplogroup R had significantly more phylogenetic diversity than what is visible today.