3-rooted lower molar rare at under 3.5% in non-Asians. Frequency exceeds 40% in Chinese and New World Asians. Trait found in 160,000-year-old Denisovan jaw from Tibetan Plateau. Denisovans occupied Asia over 160,000 years ago before Homo sapiens. Trait unique to Asian groups among modern humans. Interbreeding with Denisovans transferred trait to Asian Homo sapiens. Previous claims of archaic-modern continuity in Asia now supported by this dental evidence. Denisovans dark-skinned unlike pale Neanderthals. Xiahe mandible confirms Denisovan presence on Tibetan Plateau pre-sapiens. Trait older than sapiens dispersal from Africa.