Overview
- Researchers reporting in Nature analyzed enamel proteins from six Homo erectus teeth about 400,000 years old from Zhoukoudian, Hexian, and Sunjiadong in China.
- They found two changes in ameloblastin, a tooth-forming protein, including a new variant shared by all six specimens that groups them as a distinct East Asian H. erectus population and supports the Hexian fossils’ identity.
- A second ameloblastin variant also occurs in Denisovans, which the team interprets as evidence of gene flow between East Asian H. erectus and Denisovans roughly 400,000 years ago.
- That Denisovan-linked signal appears in living people in parts of Southeast Asia and Oceania, reaching about 21% in the Philippines and near 1% in India, consistent with inheritance via Denisovan ancestry.
- The team used a gentle acid-etching method with mass spectrometry to recover proteins without damaging the fossils, and outside experts say broader sampling and any retrievable ancient DNA are now needed to confirm the relationships and effects.