The Ancients - Cheddar Man: Science and the Skeleton

Episode Date: February 28, 2021

Cheddar Man is the oldest almost complete skeleton of a Homo sapien ever found in Britain and, for this fantastic episode, Tristan spoke to the scientist who has drilled a (very small) hole in him. Dr Selina Brace is a biologist who works with ancient and degraded DNA. At the Natural History Museum in London, where Cheddar Man currently resides, Selina and her team have been able to examine this iconic skeleton’s genetic makeup and deduce from it more information about the evolution of our species, as well as the lifestyles and even appearances of Homo sapiens moving from the Mesolithic to the Neolithic era.For more visit: https://access.historyhit.com/videos/the-first-britons

Hi, I'm Tristan Hughes, and if you would like The Ancients ad-free, get early access and bonus episodes, sign up to History Hit. With a History Hit subscription, you can also watch hundreds of hours of original documentaries, including my recent documentary all about Petra and the Nabataeans, and enjoy a new release every week. Sign up now by visiting historyhit.com slash subscribe. by visiting historyhit.com slash subscribe. It's the Ancients on History Hit. I'm Tristan Hughes, your host, and in today's podcast we've got the fantastic Dr. Selina Brace on the show.

Selina is an ancient DNA specialist working at the Natural History Museum. It was Selina who drilled into the skull of that remarkable, iconic, Mesolithic skeleton, Cheddar Man. Now, it was great to get Selina on the show to talk about her work on Cheddar Man, what they were trying to uncover through this work, and what it is teaching us about one of the biggest shifts in human history, the shift between the Mesolithic and the Neolithic, the shift from hunter-gatherers to farming societies. This was an amazing chat. You're going to absolutely love it. Here's Selina. Selina, thank you so much for coming on the podcast. It's my pleasure. Selina, thank you so much for coming on the podcast.

It's my pleasure. Now, we're talking about you and your team's incredible work on an iconic skeleton, Cheddar Man, who has this extraordinary history. Yeah, Cheddar Man is an amazing story. He is Britain's oldest, most complete skeleton. He currently resides on display at the Natural History Museum in London. He currently resides on display at the Natural History Museum in London. But his story begins, or he first came to light, should we say, in the late Victorian era in Somerset and a set of caves called Goff's Caves, which are near the village of Cheddar. These caves at the time were managed by a retired sea captain, Captain Richard Cox Gough, fabulous name. And he turned these caves into Victorian show caves. So it was a tourist attraction and people would come to the caves

and look at the stalactites and stalagmites. It was all the rage in the Victorian era, much like it is today, actually. But in December 1903, there were some workmen and they were digging a drainage ditch in these cave areas because they were actually quite prone to flooding. And when they were pulling out the soil and the sediment, they found in there these remains, these remains of an almost complete skeleton of a young man. It caused quite the media storm at the time because these were obviously really, really old bones and people were already suggesting perhaps this was remains of the oldest Englishman. And they were throwing out ideas of like maybe he was 40,000 years old, 80,000 years old. Yeah, it was quite a big deal at the time.

So looking at the remains of his skeleton, what period did he date to? Yeah, so he has actually been radiocarbon dated several times now. And we know that he died around 10,000 years ago. This means that he was alive during a period called the Mesolithic period, which is a period in Britain 12,000 to 6,000 years ago. Britain itself would have looked quite different during that time. It was warmer. We had pine and alder forests. And the people of this time would have had, obviously, a completely different lifestyle. When we think about people from this time point, so 10,000 years ago, these people were living what we call

hunter-gatherer lifestyle. They would have been living in portable animal skin tents. They perhaps took shelter in caves or spent some time there. They didn't really stay in one place, so they were quite nomadic. And we think they followed what we call a complex pattern of seasonal occupation. So they may have returned to the same place several times, but they didn't live in one place. They were working on the land. Oh, there's a site in Yorkshire, Star Carr. And we know from this site that they occupied this site at certain seasons. And we find things like beads there. So we know they had ornaments. They even had this amazing headdress made from a stag skull and antlers. And we know from the animal remains there that they were probably hunting animals such as auroch, deer, wild boar.

And so they had tools as well, axes, microliths and spears. Well, I'm glad Selina, you mentioned the mesolithic there and produced that brilliant rundown just then. Because moving over 100 years on from the initial discovery of Cheddar Man at the National History Museum, what were your team's aim with Cheddar Man? What did you want to find from this skeleton? So I'm actually an ancient DNA specialist. So we were looking to extract Cheddar Man's DNA. This was part of a much, much wider study that we were wanting to look at. And we were wanting to look at lots of individuals in Britain, but from this very specific time point. So the period

we wanted to look at is the transition from the Mesolithic period, that's what I was just talking about, the hunter-gatherer, to the Neolithic period. So this is when the culture in Britain changes from a hunter-gatherer to that of a farmer. And this is an amazing time point. It's fascinating. It's actually probably the biggest shift in modern human history. It changed their lives dramatically, like everything. They went from a very nomadic lifestyle to living in one place. They were building communities. They were building towns. It changed what they ate. So previously, they would have been quite a varied diet. As I say, they were following the seasons. And this then changes to it being quite constricted to like a cereal-based diet, things that they could farm. It probably changed their diseases that they were exposed to, because now they're living very close to each other. They're living

very close to the animals that they're domesticating. So some of the evidence certainly suggests it probably wasn't even very good for them. You know, perhaps this wasn't an excellent plan and it wasn't very good for their health. So what we wanted to explore with the DNA was about the mechanism by which this change happens. So there are many different ways this could happen. But what we wanted to specifically look at is the genome and how it changes at this time. as this could happen. But what we wanted to specifically look at is the genome and how it changes at this time. But also we wanted to look at whether or not we were seeing a migration of people coming into the UK who brought farming practices with them, or whether or not it was

actually the people in situ, so the hunter gatherers who actually started farming. So to sort of squish that down into that summary statement, was it a movement of ideas or was it a movement of people? As you say, that moment in human history, that is a huge shift, isn't it? The Mesolithic to the Neolithic transition. And before this groundbreaking study that we're going to go into in a second, were those the two main theories surrounding what actually happened at that time? Yeah, so those were the two main theories about how farming came into Britain. But there are also lots of other questions associated with that. We didn't know where in Europe they came from. We know that farming spread across Europe. It started in the east, it started in Anatolia, modern day Turkey, and we know that it spread in a westerly

direction. But we don't really know how they came into Britain, so where they came from, or even whether they came in just one route or two. So it's about the whole mechanism behind it, that there was a lot of different questions that we wanted to address. Well, let's then dive into the study itself. And one of the favourite questions I'm looking forward to asking, and I'll ask now, Selina, how do you go about extracting the DNA from one of the most famous iconic skeletons in the whole of history? Very carefully. Yeah, terrifying. I didn't want too much coffee that morning, that's for sure. Terrifying. I didn't want too much coffee that morning, that's for sure. So I work in a specialised lab. So I work in an ancient DNA laboratory. So the idea is as soon as anything dies, the DNA begins to break down. It fragments into smaller and smaller pieces.

So we have to work in essentially a super, super clean lab and we want to prevent any modern DNA from coming in. So we wear full body suits, we have gloves, masks, face shields, boots, you name it. And we have a lot of bleach, lots and lots of bleach everywhere to try and get rid of any modern DNA. So the first thing is making everything super clean. Then when we were coming to bring in Cheddar Man into the lab, obviously I only took a little bit of him, take the whole thing in. And the first thing is to drill into him and to remove a small amount of bone powder. On this occasion, we were actually drilling into his inner ear. So this is a bone called the petrous bone, and it is an incredibly dense bone. It's the densest bone in the body. And so I had his skull very carefully placed in my drilling cabinet there. And I take what's essentially

like a dentist drill. So this is a drill that goes at incredibly slow speeds, because we don't want to generate heat, because heat would degrade the DNA. I'm trying to keep that DNA as long as possible. I used a very small drill bit, about three millimeters in diameter. So that's really small. And then very, very carefully drilled into his ear to remove this little bit of bone powder. I only took a small amount, about 20 milligrams. 20 milligrams, it's actually 0.004 of a teaspoon. So it's really, really small. That's the bone powder I took from Cheddar Man. And then basically, we use chemical reactions after that to break away the bone, to wash everything away that isn't DNA. And then we prepare it for sequencing,

pop it on a sequencing machine. I mean, all of this takes days and days of work in the lab, I should point out. And then the sequencing machine tells us what these tiny fragments are, you know, the A's, C's, G's and T's. And then we put it back together again, like a big old jigsaw puzzle. The science is absolutely incredible behind that. And it would have been very audacious if you had taken the whole skull of Cheddar Man in to do that. But that's absolutely incredible. And just from this small bit of DNA, which you're able to extract through this amazing process, before we get into the big Mesolithic, Neolithic question, what were you able to find out about Cheddar Man's

appearance? So that was actually quite interesting. So we used a set of forensic tools, so used in forensic medicine today, to predict different pigmentation levels. And we looked at the pigmentation levels in his hair, his eyes, and his skin. And this is a tool that uses a statistical model that's trained on empirical, so real day-to-day data, and it estimates a probability score. And then you apply that probability score to broad categories of pigmentation. And from this, we predicted that he would have had dark brown to black hair colour, he would have had light blue or blue-green eyes, and he would have had a dark or dark-to-black skin pigmentation. And were these results that surprising?

No, not really. Not to us, anyway. It turned out that it was quite surprising for some people, and I can understand why, because this combination of a lighter eye colour and a dark skin pigmentation might seem quite unusual to us today, but this actually wasn't that unusual for people during the Mesolithic period. So other ancient genomes had already been sequenced. So there's an individual called Labrania from northern Spain, and his genome also conferred this similar appearance of a very dark skin pigmentation and a lighter eye combination. So no, to us, it wasn't that much of a surprise dark skin pigmentation and a lighter eye combination. So no, to us, it wasn't that much of a surprise, to be honest. That leads me on to the next question, the other part. We mentioned the appearance, but you've also mentioned how, of course, Cheddar Man dates to the

Mesolithic period, the diets, the big range that they had. Did we learn stuff about the diet as well from your study? Yeah. So in terms of his diet, we know the kinds of things that mesolithic period at the time were eating from animal bones that we find. But from his DNA, his DNA didn't actually tell us what he ate, but it did tell us what he couldn't eat. So he did not have the genetic variant that would have allowed him to, as an adult, digest milk. So he would have been lactose intolerant. So that's quite interesting, really. In many ways, again, a bit like the skin pigmentation, this wasn't that surprising to us because, of course, he was a hunter-gatherer, so he wouldn't have really been exposed to dairy products.

So he didn't need to have that gene variant. In fact, it's quite interesting, actually, because we don't see this gene variant that allows you to drink milk as an adult in Europe until about the Bronze Age. So that's several thousand years after we start farming that you first get this evidence of people being able to drink milk. And even then, a study that came out last year looking at people in Germany found that only one in eight people in the Bronze Age could digest milk. But then it spreads like wildfire. And in the Mesolithic period, less than 2,000 years later,

something like 60% of the population of Europe can drink milk. 60%. I know, it's crazy. It's actually like the fastest spreading gene that we've come across. And it's like the certainly the strongest evidence for positive natural selection in humans is a fascinating field. I mean, I could talk all day about that, quite frankly, but... We'll have to do a separate podcast on that but selena going on from that let's go to the moment of truth then the big question surrounding your study what did this dna from cheddar man and of course from other skeletons that you were looking into what did

it reveal about this huge shift the mesolithic to neolithic shift in early humans in britain so what we do when we analyze the the DNA from these different individuals is we basically boil it down to their similarities and their differences. So there are points in the genome where you might have the same, like you and I might both have a C, or I have a C, you have a T. And it's these similarities or differences in the genome, these particular points, these what we call SNPs, single nucleotide polymorphisms, that we use to see how similar or different people are. And when we looked at all the remains of the genomes of people who were hunter-gatherer, they all look very, very similar to each other. Then when we look at all the genomes

of people who were farmers in Britain, who are associated with this farming culture, we find that they too look very similar to each other. But when we compare the two groups together, they are completely different. They are genetically nothing like each other, totally separate at many, many different points in the genome. And so what does this all suggest, Selina? What this means is these are different people. They come from a different population. So the people who we see in Britain, who we associate with farming, have a different genetic signature, which means we have a migration of a different group of people that come into Britain around 6,000 years ago, and they bring with them this farming practices so it's not a diffusion of ideas

it's not the hunter-gatherers that just stay in situ and it's just about them starting farming we in fact see instead a group of people coming over who then start farming practices that's absolutely fascinating so could it be then selena that at the time that you see these first farmers arriving in britain they could be living side by side with hunter gatherers who've been in Britain longer time. Yeah, absolutely. So it's kind of difficult for us to tell exactly what happens at this point. I mean, I can only tell you what the genetics say and what the genetics tells us is that the signature of the people who were farming is very different to the signature of the people who were there before. So there's definitely a migration of people coming in. I suspect that they probably were living side by side. There's no signs of violence. It's not like a massive

takeover, but it is a genetic replacement. But what this can mean is just the fact that there probably weren't that many people in Britain at this time. So that genetic signature is quite weak. So they sort of drift off into the background. But what we know from the genetics is that they were not what we call intergressing. So they weren't mixing. You don't suddenly see in the next generations a mixture of hunter-gatherer and farmer. What you see instead is just this farmer signum so that's quite a different thing it doesn't mean that as i say certainly doesn't mean that was aggressive or violent it just means that that signature was quiet and that there wasn't a lot of intermixing doesn't mean they weren't living side by side it just wasn't that many of them and they were roaming

so cool i've talked to lots of ancient historians, lots of archaeologists, but like the science side, when looking at this far back, it's absolutely astonishing what you can find out from the DNA. And from this study, regardless of the shift from the Mesolithic to Neolithic occurring in Britain, do we see it contrasted with events occurring on the continent in Europe or are there similarities? There's similarities and there's differences. So in Europe, we know that farming starts in Anatolia, so modern day Turkey. And we know that there's a migration of people then who move in a westerly direction across Europe. But what we see there is a slightly difference in the way that they mix or intergress. So in Europe, what we see in the beginning is very little intergression, very little mixing. But then that changes through time, and that actually

increases. And you see a lot more mixing of these two cultures, and from the genetic side anyway. Whereas in Britain, we don't see any change in that integration. The levels stay very, very low throughout the entire period of the Neolithic. Again, as I say, this could just be because there wasn't that many people around in the Neolithic in Britain at that time. So they kind of more drift into the background than anything else. But it seems to be a slightly different process in both places. There's no resurgence. The phrase we quite often use is a resurgence in the hunter-gatherer genetics. And you don't see that in Britain, whereas you do see that in Europe. Ah, very interesting indeed. Now, I've got in my notes, ask about the Iberian link, ask about the Iberian link. Selina, what is the Iberian link? Okay, this is quite interesting as

well. I think it's quite interesting. So another question, there's always lots of questions that we wanted to look at was where in Europe did the British Neolithic farmers come from? And what route did they take? So to assess this, we look again at the DNA of the British farmers. And then we compare that to the DNA of Neolithic farmers across Europe. We apply some fancy statistical tests called F-stats. But what that basically means is, again, we use that DNA to compare one population to another. And we say, do you share more or less genetic drift with that population?

Putting it more sort of plainly is, do these populations have a shared evolutionary history? Are they more similar to each other? And when we do that, when we compare these British farmers to other Neolithic farmers in Britain, the British farmers showed the highest affinity. farmers in Britain, the British farmers showed the highest affinity. They were closest genetically. Their evolutionary history was closest from farmers from Iberia. So it looks, therefore, like the British Neolithic farmers were descended from Iberian Neolithic populations, who then would have expanded and come into Britain. What's great is that since we published this data, there are, of course, more people doing more analyses, more genomes have been sequenced.

And now we've had sequences from Neolithic farmers from France. And when they added these into the analyses, they conferred this link that we'd seen, this British-Iberian link, they conferred this link that we'd seen, this British-Iberian link, but also a connection with France. And so what we can now tell is that we can really start to nail down the route that these people would have taken to get into Britain. And it looks like they came from two different routes, all starting in Iberia, as we thought, but one of which then goes from Iberia into northern France, going along the Atlantic seaboard, and then hopping over the channel into Britain. And the other again starts in Iberia, but then spreads through southern France, central France, so Paris, the basin and Normandy, and then crosses over the channel into Britain. So it's amazing.

More genomes, more data, more answers. It's such fun absolutely that's incredible and you kind of touched on it there with this dating with the french stuff as well and thank goodness iberian so iberia mean modern day spain and portugal iberian peninsula that part of the world i guess also have there been any other amazing new genome discoveries that you and your team or research has uncovered that tells us more about this period in ancient history in northwest Europe? We have also done some work on the periods that come later. So we've looked at Bronze Age replacements in Britain as well. That's actually really interesting. We see another migration of peoples coming into Britain again in the Bronze Age, in the Beaker period. And here,

it looks like a very different thing occurs at this time point. It's fascinating. So this time, there's another migration of people come over. But now it seems that this time they're living together and we're seeing a lot more harmony, although there's more of a genetic replacement. But now when we look at these individuals, we're seeing that a lot of people are related to each other and you see the resurgence coming back. So this is showing it was a much slower process during this time, probably because there were more people living in Britain at this time. But it gets a bit complicated at certain times around this period as well, because people, their funerary rites change and people are burning bodies. Makes it a lot harder to get DNA out where people go around burning bodies.

But yeah, no, it's all the time. We're sequencing new genomes. Other groups are sequencing new genomes. It's an amazing field to work in. It really is. I feel very privileged. Absolutely. This has been an amazing chat so far, Selina.

And the last question to leave it all off on, the biggest question of them all, are we descended from Cheddar Man i'm sorry no we're probably not no as much as i'd like to say yes not really because as i've said we have these replacements so we have genetic replacements that occur when these farmers come in and then we have further genetic replacements when the Bronze Age people, the Beaker people come into Britain as well. So it's not very likely that anyone's really a direct descendant, although we do still have. If you look at people in Britain, you have a small percentage of your DNA that we can attribute to a hunter-gatherer signal, but that is very unlikely to have come from a hunter-gatherer in Britain. That would more likely have come in through when people have moved across Europe

and there's been a lot of integration and mixing up of genomes there. So sadly, no, we're not really related to Cheddar Man. You hear that, Selina? That's the sound of millions of hearts breaking right there. I'm so sorry. As you tell the truth. No, that's really astonishing. That's really, really interesting.

Selina, this has been an eye-opening chat all about Cheddar Man, the Mesolithic, Neolithic, and this early part of ancient history. Thank you so much for taking the time to come on the show. My absolute pleasure. Thank you very much for inviting me. I hope you enjoyed that podcast with the brilliant Dr. Selina Brace.

I had great fun recording it. I'm sure you could probably tell. Now, if you want to learn more about Cheddar Man, about our early ancestors on the island of Britain, well, History Hit, we've just released a new documentary all about it featuring Selina. It's called The First Britons and it's available now on History Hit TV. Head over to access.historyhit.com and look for The first Britons. See you in the next episode.