Overview
- The Nature study, published Wednesday, analyzed enamel proteins from six teeth about 400,000 years old found at Zhoukoudian, Hexian, and Sunjiadong in China.
- All six teeth shared two variants in ameloblastin, an enamel protein, including a newly reported change likely tied to East Asian H. erectus and a second change previously seen in Denisovans and some living people.
- The authors propose that interbreeding transferred the Denisovan‑seen variant from H. erectus or a closely related group into Denisovans, with later Denisovan–Homo sapiens mixing passing it to some modern populations.
- The team used a micro‑destructive acid‑etching method and a protein‑based sex test (AMELY) that identified five males and one female, showing how proteins can reveal ancestry when DNA is too degraded to recover.
- Several experts caution that the isolated teeth could belong to Denisovans or another population and say protein data alone cannot resolve the relationships, calling for more fossils and any retrievable ancient DNA.