Overview
Haplogroup R-L389 is a crucial early branch of R1b and represents the stage at which the R1b lineage began to diversify into the major forms known today. L389 is often referred to as one of the key transitional markers that connects the oldest R1b lineages, such as R-L278 and R-PH155, to the younger and more widespread branches including R-P297 and the later expansions of R-M269. As such, R-L389 is a pivotal node that anchors the deep evolutionary structure of R1b. During the period when R-L389 was diversifying, Upper Paleolithic and early Holocene populations across western Asia, the Caucasus and eastern Europe were undergoing demographic and ecological shifts driven by climate change. Groups carrying L389 likely belonged to mobile hunter gatherer communities that moved seasonally across steppe and forest steppe environments. These populations later gave rise to distinct branches associated with different regions of Eurasia. The later descendants of L389 include the major radiations of R1b that spread across Europe during the Neolithic and Bronze Age, as well as the smaller early Asian branches such as M73 and M478. The presence of L389 in early steppe populations is supported by its close relationship to lineages appearing in ancient genomes from the Pontic Caspian zone.