Friday, June 21, 2024

Bald and dark like his mummy — DNA redraws picture of Iceman Ötzi

Since hikers stumbled on his remains in the Italian Alps over 30 years ago, the Iceman “Ötzi” has given us a wealth of information about the Copper Age in which he lived. Now, a new genetic study transforms our understanding of his physical appearance and origins.

It turns out that the reality was staring us in the face. Ötzi, in life, looked very different to previous reconstructions and more like his mummified body does today. He was not fair-skinned and hairy but darker-skinned and probably balding at the time of his demise.

Ötzi lived between around 3350-3120BC and was killed by an arrow wound while crossing a ridge in the Schnalstal valley, in what is now Italy’s South Tyrol. He was about 45 years old, 5ft 3in (1.6m) and 7st 12lb (50kg) and his last meal consisted of ibex and red deer meat and einkorn wheat, possibly in the form of bread. His body was naturally mummified and preserved in the ice of the valley glacier, along with his clothes — made from leather and hide — and possessions including a copper axe, flint knife, and bow. The body and objects are conserved and displayed at the South Tyrol Museum of Archaeology.

The body of Ötzi was preserved by ice and is the world’s oldest known glacier mummy. Photo: © South Tyrol Museum of Archaeology/Eurac/Marco Samadelli/Gregor Staschitz

Genetics cannot explain the circumstances of his violent death, but the new findings include a number of significant surprises. “The genome analysis revealed phenotypic traits such as high skin pigmentation, dark eye colour, and male pattern baldness that are in stark contrast to the previous reconstructions that show a light skinned, light eyed, and quite hairy male,” said Professor Johannes Krause from the Max Planck Institute for Evolutionary Anthropology in Germany.

“The mummy itself, however, is dark and has no hair… It is remarkable how the reconstruction is biased by our own preconception of a Stone Age human from Europe.”

He added: “Over the last ten years, we have learned a lot about phenotypes in the past. One of the most exciting findings is the hunter-gatherers — the people that lived before the Iceman — all had dark skin, and probably as dark as people in Sub-Saharan Africa. That is true for all Europeans more than 8,000 years ago, which makes sense because people came out of Africa. Even for the early farmers, like the Iceman, we know they had dark skin also. It’s actually an important message for the public to know that what we call ‘white’ — this kind of light skin we have in Europe today — is a very recent phenomenon, maybe 4,000 or 5,000 years old… This is the Bronze Age, this is not the deep past.”

An artist’s reconstruction of Ötzi’s appearance, based on the new findings. Image: © Max Planck Institute for Evolutionary Anthropology

Dr Albert Zink, co-author of the study published in Cell Genomics and head of the Eurac Research Institute for Mummy Studies in Bolzano, said: “It was previously thought that the mummy’s skin had darkened during its preservation in the ice, but presumably what we see now is actually largely Ötzi’s original skin colour. Knowing this, of course, is also important for the proper conservation of the mummy.”

The research also changes our understanding of Ötzi’s ancestry. Almost all present-day Europeans are descended from a mix of three ancestral populations. Western hunter-gatherers spread across Europe after the last Ice Age and — millennia later — mixed with early farmers who migrated from Anatolia about 8,000 years ago. Subsequently, from around 4,900 years ago, pastoralists swept westward from the Pontic Caspian steppe, probably bringing Indo-European languages to many regions.

This reconstruction of the Iceman by Alfons and Adrie Kennis was made before the latest DNA results. Photo: © South Tyrol Museum of Archaeology/Ochsenreiter

A previous, 2012, analysis of Ötzi’s genome, using DNA from one of his bones, found that he was descended from all three populations, including the steppe herders. However, the timescale was puzzling as he lived hundreds of years before major steppe migrations into Western Europe are thought to have occurred. The new results suggest that the finding was false and resulted from contamination with modern DNA.

According to the latest, more sophisticated, analysis, Ötzi derived over 92 per cent of his genetic ancestry from Near Eastern farmers and the remainder from Western hunter-gatherers — and the mixing of the two groups occurred approximately 1,000-1,500 years before Ötzi’s birth. This is an exceptionally high level of Near Eastern ancestry for Europeans of Ötzi’s era.

Krause said: “After early farmers arrived in Europe between 8,000 and 6,000 years ago, there was a resurgence of hunter-gatherers. The earliest farmers that we have from, say, Central Europe or Great Britain had a very high percentage of Anatolian farmer ancestry. They had not really mixed with hunter gatherers on their way. Then, over the next 1,000 or 2,000 years, the populations mixed with the local people. And that is true for all of Europe, so that by 5,000 years ago, you had about an average of 20 per cent hunter-gatherer ancestry and 80 per cent early farmer ancestry.

An updated picture of Ötzi, alongside the previous reconstruction. Image: © Max Planck Institute for Evolutionary Anthropology

“The Iceman, however has 92 per cent early farmer. And that’s very much an exception among the hundreds of genomes from the Chalcolithic [Copper Age]. So for the time period, he’s really standing out as having the highest amount of early farmer ancestry.”

The only other ancient samples with comparable levels of Anatolian farmer ancestry are from another site in Northern Italy, but slightly earlier.

The team conclude that the Iceman came from a relatively isolated population that had very little contact with other European groups. They said the Alps probably formed a genetic barrier, meaning the Iceman’s community didn’t exchange many genes with people to the north and west of the mountain range. Krause noted that there was no sign of inbreeding in Ötzi’s genome, indicating that he belonged to a population of at least a few thousand individuals.  

Could Ötzi have been killed in some sort of conflict with people from outside his own relatively isolated group? Krause said there was no evidence for this. Nevertheless, he said the early farmers from whom the Iceman was descended have been linked to the beginnings of warfare in Europe, as farming communities attacked other, rival farming communities to seize land, animals and stored crops.

The Alpine valley in the South Tyrol, Italy, where Ötzi’s remains were found. Photo: © South Tyrol Museum of Archaeology/Dario Frasson

As for Ötzi’s lifestyle, Krause said his possessions, and the evidence for his diet, showed that it combined elements of farming and hunting and gathering. “He was probably a good hunter. But he was not nomadic. Based on his clothes and food, we can assume that he had a farming lifestyle and lived in a small village.”

Krause said there were no concrete plans for a new physical reconstruction of Ötzi, but it was likely the new findings would be taken into account in a future reconstruction at some point.

In future, he hopes to find relatives of Ötzi through analysis of other prehistoric remains — revealing more context for the Iceman’s life and times. He said: “I very much expect this will happen and it’s super-exciting. The more data we get, the higher the chances that we can find actual kin of the Iceman. Because we have very powerful new tools that allow us to look for relatedness up to the tenth degree and, at the tenth degree, each of us has over a thousand ancestors.”

He added: “We are all related to the Iceman, if he had progeny, but that is meaningless. No one today is a close relative or a closer relative than anyone else — we’ve completely lost the type of relatedness [to Ötzi] over millennia. But within a 200-year time window after and before he lived, we might find some kin that we can really call his relatives.”

The top image shows experts humidifying the Iceman’s mummy in order to ensure its preservation. Photo: © South Tyrol Museum of Archaeology/Marion Lafogler

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