The oldest human DNA ever found, from a 400,000-year-old thigh bone in Spain, may lead scientists to revise mankind’s family tree. The femur from Spain’s Sima de los Huesos, or “Pit of Bones,” yielded mitochondrial DNA that showed links between its owner and a group of ancestral humans called Denisovans, according to a study in the journal Nature. The femur bone previously had been thought to belong to the Neanderthals, while Denisovans had been found only in Siberia, about 4,000 miles east of the Spain site, the authors said.
The finding suggests that the Denisovans’ split from the Neanderthals may have occurred from 170,000 to 700,000 years ago, the scientists said. Previous evidence had indicated the two groups separated from the ancient ancestor of modern man about 300,000 years ago in Africa, with the Denisovans eventually heading east and the Neanderthals moving into what is now modern Europe. Modern man, or homo sapiens, appeared about 200,000 years ago.
The sequence “establishes an unexpected link between Denisovans and the western European Middle Pleistocene fossil record,” wrote the authors, led by Mattias Meyer at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, in the research released yesterday.
The sample is so old that it may have preceded the Denisovans’ split from the Neanderthals, and the material from the ancient humans found at the Pit of Bones may be related to both groups, according to the paper.
It’s also possible that the DNA found was passed to Neanderthals and Denisovans, and then disappeared from later Neanderthals, the authors wrote.
The sample required some detective work, since DNA generally breaks down into smaller fragments after an organism’s death. The first ancient DNA was pieced together in 1997, and was from a Neanderthal. The first Denisovan was identified in 2010, from a finger bone and a molar found in Siberia.
The previous oldest DNA discovered was from about 100,000 years ago.
