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Enamel Proteins Link East Asian Homo Erectus to Denisovans

Protein markers in tooth enamel give a rare genetic read on deep-time relatives without usable DNA.

Overview

  • A Nature study reports enamel proteins from six 400,000-year-old Homo erectus teeth in China that point to interbreeding with Denisovans.
  • The team analyzed seven teeth, including one Denisovan, by reading sequences from nine enamel proteins with liquid chromatography tandem mass spectrometry.
  • They found a new change in the enamel protein ameloblastin, labeled AMBN-A253G, in all six Homo erectus teeth, marking an East Asian population across three sites.
  • A second ameloblastin change, AMBN-M273V, also appears in Denisovans and may have reached some people today through Denisovan ancestry in Southeast Asia and Oceania.
  • Protein reads of the tooth protein amelogenin identified sex from single teeth, and researchers and outside experts say more fossils and any ancient DNA are needed to confirm the gene-flow path.