Ancient Homo Erectus Teeth Reveal a 400,000-Year-Old Genetic Link to Denisovans

Researchers from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences have recovered molecular evidence pointing to a genetic connection between Homo erectus and Denisovans, an archaic human group that also contributed genetic material to modern populations. Homo erectus was the first species in the genus Homo known to have migrated out of Africa, but a scarcity of molecular evidence has left its genetic characteristics and relationship to modern humans unresolved.

A team led by Qiaomei Fu of IVPP used a micro-destructive acid etching technique to recover enamel proteins from six Homo erectus teeth found at three Chinese sites, Zhoukoudian, Hexian and Sunjiadong, all at least 400,000 years old, while preserving the teeth's overall shape. The findings were published in Nature.

The researchers detected two mutations in the enamel protein AMBN. One, AMBN-A253G, had not previously been identified and is proposed as a marker showing that specimens from all three sites belonged to the same population. The second, AMBN-M273V, had previously been considered specific to Denisovans; finding it in these Homo erectus populations suggests it may have entered the Denisovan lineage through interbreeding and later reached some modern human populations in Southeast Asia and Oceania through Denisovan introgression.

The work also introduces new methods for studying rare fossils without destroying them, including a technique for determining the sex of ancient hominins using the male-specific enamel protein AMELY. The research was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences, the Archaeological Talent Promotion Program of China and the New Cornerstone Science Foundation.