Ötzi the Ice Man Contains Still-Living Microbes

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0:47Yes, he was a man aged about 45 when he died and we've since named him Ötzi after the Ötzel region on the border between Austria and Italy where he was found. And Ötzi the Iceman has since given up a huge amount of information about the humans that were living in Europe at that time, everything from their diet, their clothing, their societies and even really cool things like their medical knowledge. From New Scientist, this is The World, The Universe and Us. I'm Dr Rowan Hooper. And I'm Dr Penny Sarche. Yeah, so we know so much about him. He's got to be the most well-studied person from the Stone Age, right?

1:19Yeah, surely. Definitely. Copper Age. We'll get into that. This is someone. Graduation of the Stone Age, the Copper Age. So give us the top line of what we know about him. Yeah, so sort of middle age by modern standards, as I said, 45 years old and around 1.6 metres tall, which apparently is about average for a Neolithic human. If only I lived back then. Me too. He was slim and probably weighed about 50 kilograms. His hair was dark and wavy and at least shoulder length. Although he was losing his hair a bit and going a bit grey from what I've seen. His eyeballs were desiccated, but they remained in the sockets and that allowed scientists to determine that he had blue eyes.

2:04Beautiful blue eyes of this corpse. Apparently he had this very marked gap between his top two incisor teeth, something known as a diastema and he also had no wisdom teeth Okay, some other factoids about him was his clothing is really remarkable for these Stone Age, Copper Age people Well, so actually you can look at the fashion changes throughout the Stone Age and different periods So in this, there's an Alpine Copper Age and his clothing can be dated to this period Right So he had different animal skins that were matched though, and his belt matched and there was imagery carved on it that we've seen in sort of stone carvings as well that relate to that age that might relate to some sort of deity worship at the time.

2:49And he had a bearskin cap as well. So this isn't just utilitarian, it sounds like finery. Yeah, yeah. So he might have well been a tribal leader. He also had loads of weaponry, like quite prestigious stuff, like a dagger, an axe and a bow and arrow. And he had bead ornaments. So yeah, he was probably a high-ranking person. He was also probably murdered. Yeah, Stone Age drama. We'll get to that. We also know that his stomach was full, and from that we could tell what he was eating. He died with a full stomach at least. Well, at least, yeah, up there on the mountains. He ingested cereals. There were possible cheese residues and pottery grains mixed in the food.

3:31And the last meat he ate came from red deer and ibex. and that tells us about the pastoral society that he was a part of. But remarkably, we have some new information from this incredibly well-studied old guy and we're going to hear all about that today from Sam Wong. Hi, Sam. Hi. Yes, there's been a new study of Ötzi's microbiome. Previous studies have looked at the microbes in his tissues, looked at the microbial DNA there, but it's been hard to distinguish what was part of his original microbiome and what came from the environment. and there's also this question of whether the microbes are really being stopped from growing in the conditions where he's preserved in now.

4:10So now researchers have been able to do that by looking at the microbes, the DNA, all the different kinds of samples that have been taken over the years. They've identified some of the microbes that they think were part of his original microbiome and others that have colonised the body later and remarkably they do find that some of the microbes seem to be metabolically active despite the frozen temperatures that he's kept in. Okay, so we now have Ertzi's microbiome then. Yeah, so this is from his gut or from all different places on it? Well, they've taken samples from a few different places, but some of them certainly seem to be from his gut.

4:42They've identified some bacterial species that thrive in the anaerobic environment in the gut, like Treponema, Kineothrix. And based on the level of damage to the DNA of these bacteria, which accumulates over time, They're pretty sure that these bacteria lived in Ötzi when he was alive. And these bacteria are similar to the kinds of bacteria we've seen in other ancestral hunter-gatherer groups. So it seems like we're getting a glimpse of what the microbiome was like in Copper Age humans. So the Copper Age, tell us where that comes in the... It was a transitional period between the Stone Age and the Bronze Age.

5:20So stone, we used stone for ages, we carried on using stone, but then they found that copper was the easiest metal to extract and use. Yeah, the copper age was the beginning of metallurgy, and there was some bronze in there, but the Bronze Age came after the Copper Age. Yeah, and then the Iron Age. And then it was the Iron Age. So, yes, the most surprising finding is there are some of these microbes from the environment, not his original microbiome, but some of these microbes do seem to be active. They've actually become more numerous in the more recent samples. They include these kind of cold-loving or psychophilic yeasts, So this is not a complete surprise because we have found these kind of yeasts that live in glacial ice before.

6:00They have antifreeze proteins that stop their cells from completely freezing. So there's a few of these that seem to be on the Ötzi body. And when they look at the DNA, they find that one of these kinds of yeast called glacia zyma actually became more abundant between 2010 and 2019 and became the dominant strain, while the level of DNA damage in these yeasts dropped. So it looks as though these yeasts are actually metabolically active and they can potentially replicate under the conditions where the body is. So they're living on his body tissues. Yeah, that's right. So the body is being kept in a museum.

6:35He's in minus six degrees, a humidity of 99 percent. So similar to the conditions that he was found in the glacier. But there's still this biological activity going on. They can't be completely sure yet because they haven't looked for the RNA that would show that the yeast genes are active. and we don't know whether these fungi have been active for thousands of years on this body or whether they were dormant and then they sort of were revived when the body thawed out a bit. But if they are active in these storage conditions, it would be a concern for preserving his body because some of these, they've got enzymes that can break down protein and collagen so it could start to break down the mummy.

7:13But they haven't seen any evidence of damage yet. It's probably very slow, isn't it? If you're living at minus six with antifreeze, your metabolism is pretty slow. But even so, there is damage. But yeah, I think I haven't seen Ötzi, but I've seen similar preserved ancient humans, and I find it so really moving. Like, it must be an incredibly odd and moving thing to see in real life, this man preserved in this. So it's a glass box they've got in, as you say, kept refrigerated. I wonder if they should think about making it even colder. Yeah, so for now they're going to keep doing regular genomic surveillance and track whether these yeasts really are active, look for the RNA that shows that they're really active.

7:58And if they really are degrading the mummy's tissue, then they would have to think about making it colder or changing the humidity to really restrict that microbial growth. Most of us worry about memory lapses as we age, but how do you know when it's something more serious? You can explore this question in our latest New Scientist CoLab feature, where Dr Tim Beanland separates dementia myths from scientific facts. He discusses the breakthrough drugs showing promise in slowing Alzheimer's, the potential for simple finger-prick diagnostic tests, and the incredible finding that nearly half the dementia cases globally could be prevented through lifestyle changes.

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9:15Hank makes the pizza. Copilot handles the spreadsheets. Learn more at m365copilot.com slash work. So what about his tattoos? These are quite intriguing. Yeah, he has 61 tattoos. Some of them look like... 61? Yeah. Some of them look like bar codes. Like most people today. You either have none, one or loads. Yeah, he would have fit in East London. So, yeah, lots of them are just kind of lines. They look a bit like barcodes. Some of them are crosses. But they were made by repeatedly puncturing the skin with a needle and then rubbing charcoal or soot onto them. But the interesting thing is they think this might have been a kind of medical treatment, a bit like a primitive kind of acupuncture.

9:57Lots of these tattoos are on parts of the body that show some wear and tear in the joints. Like they think he had arthritis and maybe this was a kind of pain relief. Wow. So that's a really interesting, this very early sort of start thinking about medical conditions and treating them and how you could do it. Even if it, well, presumably they got some effect. It wasn't just completely symbolic. Well, if Neanderthals can be dentists, as we discussed a few weeks ago. And what about this idea then that he was murdered? Yeah. So there's a wound in his back. I think the arrowhead as well is still in there.

10:34So he didn't die instantly from it, but it looks like he had a bad wound in the back. Maybe he was fleeing. Maybe there was a coup and the leader was shot and he ran off into the mountains. But yeah, he was on his own in the mountains and died up there from the wound. So one of the other studies that looked at his gut microbes as well, they found this Helicobacter pylori. So it's a type of gut bacteria. It's very common. About half the world's population has it. Is that the one that causes stomach? Yeah, that's right. So it's actually normally harmless, but it can cause stomach ulcers. It's been linked to gastritis and stomach cancer.

11:12Ötzi seemed to have a type of H. pylori that was associated with inflammation of the stomach lining. And there are samples from his stomach that have proteins linked to inflammation. So that suggests that Ötzi had some kind of stomach inflammation when he died. We can't really tell if it was affecting him. Sometimes people have inflammation. It doesn't bother them. but yeah it seems he might have had some sort of stomachache. I just love that, I mean we don't know this but say he was killed in a coup, he was murdered but he's gone on to become more well known than any of those ones that killed him and we're celebrating him thousands of years later.

11:45Talking about his guts. What about his tool kit? Because that's the really cool, all the little items he had in his pouch. I think this is really charming because he was found with all kinds of cool stuff, intriguing different types of fungus and things as well as six tools And the tools, for example, they're made of chert, which is one of these rocks that was used to make prehistoric tools. And you can tell a lot from these, just like all the other studies of every single bit of Etsy have told us a lot. So he was right-handed. And also you can tell that he took really good care of his tools, so sharpening them, reshaping them.

12:19He carried a little antler with him, which he used to retouch blades and sharpen them up. But there's this sort of poignancy, as there is with a lot of stuff around Etsy, that his tools have become so worn down that they were reaching the point of no repair. And so there was this analysis in 2018 where researchers suggested that Ötzi was actually in a really critical situation during his last day. So maybe he was on the run after being ousted. And he seems to have run out of any way to make new arrowheads, for example, or keep his kind of essential toolkit in repair. And you might think, oh, well, can he just go off and get another rock and fashion it?

12:55But as with so much of the studies into Earthsea, it reveals what it was really like at that time. You know, the rocks that were used to make his tools weren't just ones he would have found on the roadside. They came from as far as 70 kilometers away. And so when you look across his toolkit, the rocks are coming from at least three different areas. So there's kind of an import network. Wow, trading. Yeah, exactly. And somehow he'd got shut off or cut off from being able to sort of replenish his supplies. So yeah, chert is this rock that when you flake it, it's not flint, but it's a sedimentary rock and it shears really nicely.

13:31It makes lovely sharp edges. Yes. So good for cutting up things and shaping things. But yeah, you mentioned the fungus. He had this medicinal fungus. He had an awl, A-W-L, which is like a stick or something for making holes. I've just got my first awl. For making a belt hole. Tinder fungus. Tinder fungus. For starting fire. Very cool, yeah. And a needle. for repairing his clothes or for tattooing maybe self tattooing and acupuncture self tattooing and acupuncture so look I mean I do think it's really moving that we're finding so much more about him continuously and then this extra thing showing that he lives on in some sense or his ecosystem of Ertse lives on you know thousands of years after he's died we're still learning this thing so one of the researchers said well, you know, maybe we should consider these sort of slow living microbes to be part of the remains.

14:29Consider the hollow biome of Ertse. Yeah, I was just thinking, you know, if we cast our minds back to 1991 when they found him, we weren't really thinking about the microbiome at all. And when they put him into cold storage, it was with a view to preserving him and preventing any decay. But now, of course, we know how important microbes are, and we're just sort of desperate to know what was actually going on in his gut. well so we're bound we will find out more there's going to be another Ertzie story yeah that's all for this episode thanks to our guest Sam Wong and thanks to you for listening and do follow wherever you get your podcasts bye for now bye bye