Enamel clues link Homo erectus to Denisovans in a web-like human tree
Scientists extracted ancient enamel proteins from six Homo erectus teeth found in three sites in China (about 400,000 years old) using a new, minimally invasive enamel-etching technique. They identified two shared amino acid variants, one of which also appears in Denisovans and some modern humans, suggesting interbreeding between Homo erectus, Denisovans, and Homo sapiens and supporting a networked view of human evolution. The study relied on proteins (not DNA) and analyzed teeth from Hexian and Zhoukoudian, with five males and one female identified, highlighting open questions about how these populations relate to each other.