A new analysis of 400,000-year-old teeth has provided unprecedented insights into the interactions between early human relatives, revealing that Homo erectus may have interbred with Denisovans and, indirectly, with modern humans.
The study, led by Qiaomei Fu of the Institute of Vertebrate Paleontology and Paleoanthropology in China, examined enamel proteins from six H. erectus teeth found in China. The teeth contained two key mutations in a tooth enamel protein, one of which is unique to East Asian H. erectus, while the other is also found in Denisovans and a small fraction of modern humans.
This suggests that H. erectus passed genes to Denisovans, which later reached modern humans through interbreeding with Denisovans. Paleoanthropologist Ryan McRae of the Smithsonian National Museum of Natural History, who was not involved in the study, called the findings 'a really cool and exciting way' to trace modern human ancestry.
However, the exact relationships remain unclear. McRae noted that H. erectus could simply be an ancestor to Denisovans, who inherited the genes over time. Fu emphasised the need for more DNA evidence to clarify how H. erectus relates to other human species.
