A 400,000-year-old femur from the Pit of Bones in Spain has yielded the oldest human genetic information to date.
The previous oldest sample dates back some 100,000 years, meaning this new analysis stretches the human genetic story back a further 300,000 years or more.
The femur comes from a cave at Atapuerca, northern Spain, a site that contains some 6,000 human fossils from about 28 individuals. The cool conditions in the cave mean the fossils are exceptionally well preserved.
An international team of researchers reported their results in the journal Nature this week. Museum human origins expert Prof Chris Stringer said the result was a ‘breakthrough’ and that other fossils of the same age are now being tested.
The results of the DNA testing are surprising. While the humans in the Spanish cave physically resemble Neanderthals, they appear genetically to be most closely related to a different type of early human, the Denisovans, so far found only in Siberia.
The DNA used in this study was from the mitochondria, a part of the cell that only carries genetic information forward through females. Nuclear DNA, passed down from both parents, gives a more complete picture of genetic history, but is harder to extract from ancient samples.
‘Nuclear DNA will be needed to get a fuller story of the relationships of these ancient fossils,’ said Prof Stringer. ‘This would have been considered out of the question for material of this age until now, but techniques are advancing so quickly that this should be possible one day soon.’
Prof Chris Stringer is helping to create the Museum's new exhibition Britain: One Million Years of the Human Story, opening February 2014.