Tianyuan man lived 39,000-42,000 years ago near Beijing. Represents earliest East Eurasian lineage ancestral to East Asians, Southeast Asians, Siberians, Native Americans. Genetically diverged from European ancestors before 40,000 years ago. Belongs to mtDNA haplogroup B and Y-chromosome K2b. Lacks Neanderthal-like mandibular features of archaic West Eurasians. Shows southern equatorial morphology from Asia-Pacific colonizers. Diet heavy in freshwater fish. Tianyuan lineage basal to modern East/Southeast Asians, not directly ancestral. Tianyuan modeled as 61% Onge-like Southeast Asian plus 39% deep East Eurasian from Siberian IUP. Exhibits highest Denisovan ancestry among East Eurasians. Shares excess alleles with GoyetQ116-1 from Belgium due to shared IUP ancestry. Tianyuan cluster widespread in Paleolithic Northeast Asia but replaced by Ancient Northern East Asians during Last Glacial Maximum. Lacks derived EDAR allele present in later Northern East Asians. Contributes 21-24% to ancient East Asians alongside 76-79% Onge-related. Tianyuan-like ancestry forms 29-50% of Ancient North Eurasians. Salkhit man from Mongolia derives 75% Tianyuan-like ancestry. Low Tianyuan gene flow into Upper Paleolithic Sungir Russians. Basal East Asian ancestry from Tianyuan peopled Southeast Asia before Austroasiatic/Austronesian expansions. Shares more alleles with Surui, Karitiana, Chane Native Americans than other indigenous Americans.