The hominin family tree is more like a complicated, tangled bramble.
Homo sapiens is the only member of the genus left today, but in millennia past, the world was inhabited by multiple related Homo species – including the Neanderthals, Homo erectus, and Homo habilis, and traces of a mysterious group known as the Denisovans.
In recent years, evidence has emerged that these populations did not live in isolation. Multiple overlapping human groups roamed Eurasia, occasionally fighting, trading – and even interbreeding.
Now, new evidence has emerged of this complex history. From three sites across China, archaeologists have identified proteins in six H. erectus teeth that contain a genetic variant also seen in Denisovans, hinting at genetic mixing between the groups.
Because organic material degrades so efficiently over time, peering into our ancient past is difficult. Teeth are a particularly valuable resource. The hard enamel retains proteins that can be linked to DNA variations inherited across generations.
