Abstract
Cultural and material exchange between groups across the mountainous region separating the East Asian Steppe and the plains and river valleys of northern East Asia has been documented since the Paleolithic, yet the extent to which these interactions reflect prehistoric population dynamics is unknown. By sequencing and analyzing 35 ancient genomes from the southeastern Mongolian Plateau, spanning from 8,800 to 5,000 years ago, we found that Early Holocene populations from the southeastern Mongolian Plateau shared a common ancestry. We show this ancestry, which was predominant in steppe populations before the Holocene and may have been associated with the post-Last Glacial Maximum (LGM) microblade dispersal, to have lasted on the southeastern Mongolian Plateau until between 7,500 and 5,700 years ago, during which time it contributed to the West Liao River basin populations associated with the Hongshan culture. The continuity of the Early Holocene southeastern Mongolian Plateau ancestry was later disrupted by genetic influxes from both the northeastern Mongolian Plateau and West Liao River Hongshan populations, coinciding with cultural diffusion between 5,700 and 5,000 years ago. These revealed complex genetic and cultural interactions along the Eastern Steppe in the period between the LGM and the Middle Holocene.