A team led by Qiaomei Fu of the Chinese Academy of Sciences has recovered proteins from six Homo erectus teeth found at three sites in China, all about 400,000 years old. The fossils are far too old for DNA, but enamel proteins can survive much longer.
All six teeth carried a protein variant never seen in any other human relative, which settled a long debate over whether some of the fossils belonged to Homo erectus at all.
A second variant was shared with Denisovans, an archaic human group known mostly from a cave in Siberia. The matching gene appears today in about 21% of people in the Philippines and about 1% in India.
The researchers say the likeliest explanation is that Homo erectus passed the variant to Denisovans, who later passed it to the ancestors of people now living in south-east Asia and Oceania. The study was published in Nature.
