Hohlenstein-Stadel cave rewrites history of Neanderthal-human relations
Mitochondrial DNA analysis suggest greater Neanderthal diversity, influenced by interbreeding with a previously unknown migration of humans from Africa. Tim Wallace reports.
About 124,000 years ago in a valley in what is now southern Germany, there lived a member of a Neanderthal tribe. The sole remaining evidence of that ancient human’s existence is a single thigh bone, discovered in 1937 during a test excavation at the mouth of a cave known as Hohlenstein-Stadel, a site of archaeological interest since the early 1860s.
The bone would lie in the repository of the Ulmer Museum for decades before its Neanderthal status was confirmed, by a detailed morphological analysis published in 1992.
Now, several more decades on, mitochondrial DNA analysis has shown that it belonged to a Neanderthal unlike any other so far discovered. So different, in fact, that it calls into question everything we thought we knew about the evolution of modern humans and their migration from their birthplace in Africa to the rest of the planet.
That analysis, led by scientists from Germany’s Max Planck Institute for the Science of Human History and the University of Tübingen, shows the Neanderthal found at Hohlenstein-Stadel (dubbed HST by researchers) was part of a lineage very different from all other Neanderthal remains so far studied. HST’s mitochondrial lineage, they estimate, diverged from all other known Neanderthals at least 220,000 years ago.
Not only do the differences indicate a Neanderthal population larger and more genetically diverse than previously thought, the researchers report in Nature Communications, but HST’s mtDNA indicates “introgression” (interbreeding, in other words) between Neanderthals and hominins genetically closer to modern humans somewhere between 470,000 and 220,000 years ago, after the divergence of Neanderthals and modern human mtDNA but before HST and the other Neanderthals diverged – long before the first Homo sapiens are usually believed to have migrated “out of Africa”, about 70,000 years ago.
This points to an earlier migration from Africa to Europe of a hominin group that introduced their mitochondrial DNA to the Neanderthal population.
Mitochondrial DNA – which is contained in the mitochondria, the energy-producing machinery of cells – is distinct to nuclear DNA – contained in the cell's nucleus – in being only inherited from the mother. It has proven easier to retrieve mtDNA from ancient specimens where poor preservation and high levels of modern human contamination have made retrieving nuclear DNA all but impossible. This is the case with HST.
These results add to a radical rethink of how long ago modern humans evolved and began roaming the planet. It tends to support the findings published in June (also involving Max Planck researchers) that indicate Homo sapiens (or at least an extremely close relative) emerged 300,000 years ago – a full 100,000 years earlier than previously thought.
HST’s secrets are the second truly remarkable revelations into our ancestry unearthed from the Hohlenstein-Stadel cave, elevating the site’s significance in the archaeological books.
The cave has also yielded one of the oldest examples of figurative art ever discovered – a 31-centimetre-tall figurine with a humanoid body and head of lion. The sculpture, known as the Löwenmensch (or Lion-man) was carved from the tusk of a mammoth about 40,000 years ago. The figurine was assembled from more than 200 fragments that had been collected at the cave in 1939. Somewhat like HST’s femur, though, they lay forgotten in the vaults of the University of Ulm for 30 years until 1969 when archaeologist Joachim Hahn realised their significance from carving traces on the fragments and put them together. The figurine, and similar sculptures found in a nearby cave, has led to theories that the people who lived there practised some form of shamanism.
Whether HST lived in or near the cave, though, is questionable. As the researchers of the new study note, the absence of the femur bone’s ends and presence of gnawing marks made by animals with large teeth, as well as the absence of other remains from archaic humans in the cave, suggest the Neanderthal was brought there – posthumously, we can hope – by carnivores.