An international team of scientists has sequenced nuclear and mitochondrial DNA extracted from remains of a 40,000-year-old human found at the Tianyuan Cave site near Beijing, China. The results show Tianyuan humans shared a common origin with ancestors of many present-day Asians and Native Americans.
Humans with morphology similar to present-day humans appear in the fossil record across Eurasia between 40,000 and 50,000 years ago. The genetic relationships between these early modern humans and present-day human populations had not yet been established.
The team, including Dr Svante Pääbo and Dr Qiaomei Fu from the Max Planck Institute for Evolutionary Anthropology, extracted nuclear and mitochondrial DNA from a leg bone found in 2003 at the Tianyuan Cave site, located outside Beijing.
For their study, described in the Proceedings of the National Academy of Sciences, the scientists used new techniques that can identify ancient genetic material from an archaeological find even when large quantities of DNA from soil bacteria are present. They then reconstructed a genetic profile of the leg’s owner.
“This individual lived during an important evolutionary transition when early modern humans, who shared certain features with earlier forms such as Neanderthals, were replacing Neanderthals and Denisovans, who later became extinct,” Dr Pääbo said.
The findings reveal that the Tianyuan human related to the ancestors of many present-day Asians and Native Americans, but had already diverged genetically from the ancestors of present-day Europeans. In addition, this early modern human did not carry a larger proportion of Neanderthal or Denisovan DNA than present-day people in the region.
“More analyses of additional early modern humans across Eurasia will further refine our understanding of when and how modern humans spread across Europe and Asia,” Dr Pääbo concluded.
Bibliographic information: Qiaomei Fu et al. DNA analysis of an early modern human from Tianyuan Cave, China. PNAS, published online before print January 22, 2013; doi: 10.1073/pnas.1221359110