TLDR
A jawbone shows that an extinct human group lived on the Tibetan Plateau at least 160,000 years ago. They survived in this cold, oxygen-poor highland long before modern people arrived there.
Summary
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1 Study Aim
The study aimed to identify a fossil mandible from Xiahe on the Tibetan Plateau and determine when its owner lived. The authors tested whether the fossil belonged to Denisovans (an extinct human group) and what it revealed about their high-altitude occupation. They also examined whether its anatomy matched other ancient human fossils. The research sought to establish who made this early highland occupation possible and how long ago it occurred.
2 Study Design
The researchers examined one partial mandible from Baishiya Karst Cave, located about 3,280 metres above sea level. They compared its anatomical features with those of other ancient humans. U-series dating (a radioactive method for estimating age) was applied to carbonate attached to the fossil. The team also used palaeoproteomics (identifying ancient proteins) to study preserved collagen (a structural protein). They compared protein sequences through phylogenetic analysis (testing evolutionary relationships) when ancient DNA was unavailable. The researchers combined anatomy, dating, and protein evidence to identify the fossil and establish its minimum age.
3 Findings
The study dates the mandible to at least approximately 160,000 years ago, during the late Middle Pleistocene (a period of the Ice Age). Its robust form and large teeth resemble Denisovan fossils and other archaic humans. Preserved collagen peptides identified the mandible as Denisovan rather than Neanderthal or modern human. The finding demonstrates that Denisovans occupied the Tibetan Plateau in a cold, low-oxygen environment long before modern humans reached the region. It provides direct fossil evidence for their high-altitude presence and extends knowledge of their geographic range. The authors recommend further fossil and molecular research to clarify Denisovan history. An ancient jawbone confirms that Denisovans lived high on the Tibetan Plateau more than 160,000 years ago.