A recent study of the genomes of two of the most famous species of ancient humans - Neanderthals and Denisovans - has revealed a new, previously unknown ancestor of modern humans.
There is a possibility that this unidentified ancestor actually belonged to Homo erectus, which is believed to have died out more than 100, 000 years ago. But since not a single sample of Homo erectus DNA has been found in the world, one cannot be sure of this.
As part of this study, scientists at Cold Spring Harbor Laboratory (USA) used the ARGweaver-D Bayesian algorithm to study patterns within genomes - in this case, the DNA of two Neanderthals, one Denisovan, and two modern Africans. The resulting model can compare the facts of DNA mixing with specific historical periods of time. As a result of her work, it turned out that about 1% of the DNA of the ancient Denisovans has an origin unknown to science.
Approximately 15% of the discovered "super-ancient" regions of DNA that were found in the genome of Denisovans are still present in the genome of modern humans. What happened to the lost species from which we got them remains to be seen.