Genome sequencing data from modern humans, as well as from archaic humans like Neanderthals and Denisovans, allows reconstructing our demographic history going back hundreds of thousands of years. Last year, a paper found evidence for two separate human populations that diverged 1.5 million years ago came back together in an admixture event 300,000 years ago.
Now, a paper shows that besides Neanderthals and Denisovans, there have also been “ghost” introgressions into the human population: Gene-flow from archaic humans that, unlike Neanderthals or Denisovans, have until now left no trace.
Nehaveigur 