We know very little about the past
All groups studied, from British and Bengali people to Peruvians and Puerto Ricans, had a dense cluster that closely matched the Altai Neanderthals. Some populations also had a cluster that matched the Altai Denisovans, which was particularly pronounced in East Asians.
The surprise was a third cluster — not like the Neanderthal DNA and only partially resembling the Altai Denisovans. This, the authors concluded, was a second and separate pulse of Denisovan genes into the DNA blender.
