The BA around Xinjiang was predominantly represented by western Steppe–related ancestries, which included the EMBA Yamnaya/Afanasievo cultures (28, 40, 42, 48). For instance, we find that the WSteppe_EMBA populations cluster with individuals from the Songshugou site in northern Xinjiang (NSSG_EMBA) in multiple haplogroups (U4, U5, H2, H6a, and W3). This is consistent with the Afanasievo-style relics at Songshugou (SSG) and the physical anthropology of an individual from this site (tomb M15) who shows European-like characteristics (49). We also find evidence for the influence of Chemurchek culture in BA Xinjiang, as suggested by the archaeological records of standing stone pillars with anthropomorphic figures around different cemeteries (50). The BA populations within Xinjiang were quite mixed genetically, as we found the presence of both East (NEA) and West (western Steppe–related) Eurasian mitochondrial haplogroups. Despite high admixture among the BA Xinjiang people, some unique genetic affinities are still observed. For example, western Steppe–related populations appear to have affected the northern and western Xinjiang populations (NWAfana_EMBA and NChemur_EMBA) more notably than the eastern Xinjiang groups (E_BA and E_LBA), which showed more NEA connections. The NEA connection is consistent with the archaeologically hypothesized formation of the earliest known culture in BA eastern Xinjiang, the Tianshanbeilu culture (~3900 BP). It has been suggested that the Majiayao/Machang culture in Gansu Province, east of Xinjiang, formed the Tianshanbeilu culture in eastern Xinjiang and formed the Siba culture in the Hexi Corridor (51). Individuals from BA eastern Xinjiang (E_BA; Tianshanbeilu culture) also showed physical similarities to populations from the Gan-Qing region (52). Consistent with these reports, we found that later LBA populations in eastern Xinjiang also had genetic connections to ancient Gan-Qing populations (GQQijia_BA and GQKayue_LBA). The presence of some West Eurasian–related haplogroups in eastern Xinjiang (both E_BA and E_LBA) is further consistent with the presence of burial forms, ornaments, and tools at the Tianshanbeilu site that share some West Eurasian features (53, 54), as well as some individuals that had European-like physical characteristics (55).
https://advances.sciencemag.org/content/7/14/eabd6690