Overview
- The Nature paper, which appeared Wednesday, reports protein sequences from six Middle Pleistocene teeth in China that point to gene flow between Homo erectus and Denisovans.
- Researchers recovered enamel proteins from teeth assigned to Homo erectus and found two shared changes in ameloblastin, including a new A253G marker and the M273V variant known in Denisovans.
- The teeth came from Zhoukoudian, Hexian and Sunjiadong and date to roughly 400,000 years ago, placing the potential contact zone in East Asia during a period when multiple human lineages overlapped.
- The same M273V signal occurs in Denisovan fossils from Siberia and Harbin, including individuals carrying both versions of the amino acid, which fits mixing between these groups and a later route of variants into some modern humans via Denisovans.
- External experts praise the advance but warn that isolated teeth and early-stage protein methods allow other readings, including that the teeth are Denisovan or a related population, and they call for more fossils and ancient DNA to pin down identities and timing.