DNA from an ancient unidentified ancestor was passed down to humansChristian Fernsby ▼ | August 7, 2020
A new analysis of ancient genomes suggests that different branches of the human family tree interbred multiple times, and that some humans carry DNA from an archaic, unknown ancestor.
Denisovans Old humans
Roughly 50,000 years ago, a group of humans migrated out of Africa and interbred with Neanderthals in Eurasia.
But that's not the only time that our ancient human ancestors and their relatives swapped DNA.
The sequencing of genomes from Neanderthals and a less well known ancient group, the Denisovans, has yielded many new insights into these interbreeding events and into the movement of ancient human populations.
In the new paper, the researchers developed an algorithm for analyzing genomes that can identify segments of DNA that came from other species, even if that gene flow occurred thousands of years ago and came from an unknown source.
They used the algorithm to look at genomes from two Neanderthals, a Denisovan and two African humans.
The researchers found evidence that 3 percent of the Neanderthal genome came from ancient humans, and estimate that the interbreeding occurred between 200,000 and 300,000 years ago.
Furthermore, 1 percent of the Denisovan genome likely came from an unknown and more distant relative, possibly Homo erectus, and about 15% of these "super-archaic" regions may have been passed down to modern humans who are alive.. ■