Neanderthals and Denisovans interbred with modern human ancestors, leaving behind telltale DNA in our genomes. Now we have evidence of modern human interbreeding with two older but unknown ancestors

Journal Article

Snippet:

One of the unknown ancestors, which the researchers refer to as a ghost ancestor, interbred with modern humans in Africa prior to 50,000 years ago, before the most recent migration of Homo sapiens out of Africa into Europe and Asia. These genes comprise around 1% of the genomes of modern humans, comparable to the amount of Neanderthal DNA in the human genome. That unknown hominin lineage actually split off from the modern human lineage around the same time that Neanderthals and Denisovans diverged around 800,000 years ago, though they interbred with modern humans earlier.

The other mysterious ancestor — what the researchers call a super-archaic ancestor — was a hominin descended from a 1.8 million-year-old lineage that interbred with Denisovans in Eurasia, likely more than 200,000 years ago. Denisovans later shared some of the super-archaic DNA with modern humans through interbreeding with Homo sapiens.