Carolyn Freiwald: What Can Our Teeth Tell Us About Where We Come From? Much of our ancestral histories can be found in our bones. Archaeologist Carolyn Friewald traces the story of human migration through the hidden clues in our bones and our teeth.
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Carolyn Freiwald: What Can Our Teeth Tell Us About Where We Come From?

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Carolyn Freiwald: What Can Our Teeth Tell Us About Where We Come From?

Carolyn Freiwald: What Can Our Teeth Tell Us About Where We Come From?

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MANOUSH ZOMORODI, HOST:

It's the TED Radio Hour from NPR. I'm Manoush Zomorodi So a few years ago...

CAROLYN FREIWALD: I was in my office here in Mississippi - it's in Oxford, northern Mississippi - and an archaeologist I work with came in and asked me if I wanted to help relocate a cemetery.

ZOMORODI: This is Carolyn Freiwald.

FREIWALD: Normally when someone asks you to move a body, you wonder, OK, when are the police going to show up? Or at least you should.

ZOMORODI: But Carolyn wasn't worried because she is a bioarchaeologist. She finds clues from our past by studying our bones.

FREIWALD: Because it sort of brings a person back to life - I kind of hope somebody studies my bones, if possible - when I'm dead, though.

(SOUNDBITE OF MUSIC)

ZOMORODI: That day, Carolyn was asked to examine the bones from an abandoned cemetery near Jackson, Miss.

FREIWALD: The cemetery was last used about 100 years ago.

ZOMORODI: Oh.

FREIWALD: And it probably included a span of time of maybe the 1840s into the 1940s. And nobody had really been there for decades. And my role on the project was going to be to help study the people themselves, their skeletal remains, to see a little bit about how old they were, how they were buried, if they had health conditions or even what their lives were like.

(SOUNDBITE OF MUSIC)

ZOMORODI: Carolyn thought they'd uncover the remains of just a couple dozen bodies. But as it turns out...

FREIWALD: It wasn't just 40 graves; it turned out to be more than 350. And so the cemetery was a lot bigger than we originally anticipated. So it turned out to be a really big job. But with all of those graves, 15% of the people buried in the cemetery had a name recorded either on a stone or perhaps in the historic records. And we wanted to try and understand who the other people were who had lived and died in that area.

(SOUNDBITE OF MUSIC)

ZOMORODI: So who were some of the people you found? Like, what do you know about them?

FREIWALD: So we know that some of the people in the cemetery came from eastern states. So we have people whose gravestones say, for example, like Richard M. He was born in South Carolina, and we think that he came through Alabama and then decided to move his family and his household to Mississippi. Historic records show that he was a planter. And with him, he brought some of his family because we know there were other people with his last name in the cemetery. But we also know that he held 31 enslaved people. And it's pretty likely that he brought some or all of them along from South Carolina to Alabama to Mississippi to establish a plantation here. That also means that the Cherokee, the Chickasaw, the people who are living here, were forced out.

So in a way, this is a snapshot of how the U.S. was formed. You have people who have European ancestry. You have people whose ancestors came from Africa. And we didn't expect to find that. I didn't expect to be able to study migration in Mississippi. But once we started to look at the people here to try and figure out who they were, that's what we found. More than, you know, 10 to 15% of the people who we were able to study in the cemetery weren't from Mississippi. They weren't born here. They came here from someplace else. So we're finding that instead of migration being an anomaly, that it's actually the norm. This is what people do. They move.

(SOUNDBITE OF MUSIC)

ZOMORODI: Migration is part of everyone's history, even if you've never traveled far. A hundred-thousand years ago, our early ancestors began moving within and then out of Africa, spreading across the globe. Since then, migration has shaped empires, countries and cultures, while debates over borders and who can and can't migrate continue to this day. And so on the show today, Migration, ideas about the search for a place to call home. For bioarchaeologist Carolyn Freiwald, our bodies tell our migration story.

(SOUNDBITE OF TED TALK)

FREIWALD: I want you to think about the image that you see when I say one word - migrant.

ZOMORODI: She continues from the TED stage.

(SOUNDBITE OF TED TALK)

FREIWALD: You may have pictured a crowded boat in rough waters, people clinging to the top of a freight train or crossing a desert wearing worn-out shoes. This is what we see in the news cycle 24 hours, day after day, story after story - people who are desperate, fleeing wars, fleeing climate change, fleeing poverty. But in reality, most people move for more common reasons - to get a good education, to find a job, to find family members or to fall in love. And this is nothing new. Archaeologists like me have been studying migration and finding that people, for hundreds and even thousands of years, have been moving around the globe, from Europe's earliest farmers to Vikings to pirates, Roman gladiators and even Neanderthal cavemen, people like you and me. Mobility is one of the things that makes us human. People move. And we know this because of something that you brought with you here tonight. You carry it with you to many places - to work, to the gym, to bed and even in the shower. It's not your cellphone; it's you. It's your body and your bones, all 206 of them - I brought mine - because your bones will tell the story of your life, even a single tooth.

(SOUNDBITE OF MUSIC)

ZOMORODI: OK. So how is it that a single tooth can tell the story of my life?

FREIWALD: So, for example, if you have Native American or Asian ancestry, the shapes of your teeth, like your incisors, will be different than people whose ancestors came long back from Europe or from Africa. So if you take your tongue and run it along the back side of your teeth...

ZOMORODI: OK. I'm doing it now. Hang on. Hang on. OK. Yeah, running it along.

FREIWALD: If you feel just a flat shape, you may have some European ancestors. Yep. If you feel a little scoop shape, that can tell you that some of your ancestors originally came from Asia. And that can include, you know, having Indigenous ancestors here in the U.S.

ZOMORODI: Huh.

(SOUNDBITE OF TED TALK)

FREIWALD: If we go inside the tooth, so the pulp cavity, we may be able to extract the DNA and see if your ancestors came from Egypt or England or both. But we're not interested as much in your family's migration history as yours. And we're - that's where we go to the tooth enamel, what it's made out of, to try and find out if a person moved and even when they moved. And it's based on one simple idea - that you are what you eat. All the minerals and the elements in the food, like calcium, oxygen - which is the O in H2O - sodium and salt, can tell us something about your diet. So we know if you like cornbread or white bread, if you prefer pork, chicken or if you really like seafood. There are other elements that tell us where that food came from, and that includes sulfur, strontium, oxygen and even lead, which, of course, you don't want very much of. But these tell us where the food comes from, and that can tell us where you were when you were eating it. And that is what archaeologists use to identify ancient migration.

ZOMORODI: That's fascinating. Do you think it would - would your work be done differently if you were studying the bones of migrants today? I mean, I guess, you know, my own parents are immigrants to the United States. I - you'd know about the flat - my flat front teeth (laughter). But like, would you know that I - it's embarrassing to say, but I had, like, vitamin D gummies yesterday and that this morning I had, like, five cups of coffee? Would you be able to tell?

FREIWALD: Well, you can think of - all right. Your body tells stories in lots of ways. So with modern people, you can look at your teeth. Your teeth formed during childhood. Your bones are forming continuously. So if I stop for a second...

(SOUNDBITE OF MUSIC)

FREIWALD: ...You just formed some new bone cells. So they'll contain records of different things at different parts of your life. And think - you know, your hair grows pretty fast. So with, say, an inch of hair growth, you might have a snapshot of a month of your life. So scientists can actually do things like look for extreme stress and malnutrition that's recorded by some of the elements. If you had a change in your diet from a major food source - let's say you grew up eating meat, and then you decided that you wanted to be a vegan or vegetarian for a while, we could eventually see those changes if you were willing to volunteer a bit of your bone or hair. But figuring out where someone comes from, that's tricky because think about your food. If you wrote down what you ate in the past 24 hours, there's probably not much of it that came from where you're living right now.

ZOMORODI: Right.

FREIWALD: Bottled water, you know, Fritos, whatever your favorite snacks are - it might - we might be able to look at combinations of food because people are doing that to try and understand missing persons and migrants today, in particular, the problems of people crossing the southern U.S. border. A lot of times when they don't make it, they don't have ID with them anymore. The desert's a rough place. So we're trying to understand where they came from to get at who they were. And it becomes really tricky. But we're trying to understand how to use these technologies to bring the people back home.

ZOMORODI: Oh, that's unbelievable. And I guess I'm wondering that now that you have this technology at your disposal, is it common to examine a person's bones and find that they come from somewhere else?

FREIWALD: Yeah. That's one of the things that we found with sort of these new technologies, especially with the advent of DNA and being able to look inside people's bones, not just at the shapes of their bones, is that people in the past thought that, you know, societies like the ancient Romans, they would write about the census, who lived in their cities. And they were pretty cosmopolitan areas. But in other places, especially going farther back in time, we didn't think people could move, or we didn't think they moved that much. But now people are doing studies around the world from Mesoamerica, the Aztecs, the people who are living in North America. All across time and across space, we're finding immigrants. And sometimes you couldn't differentiate them. You'd have a person who was born locally and a person who migrated into the town buried right next to each other, the same way that you'd treat family.

ZOMORODI: Huh. So do you think movement is a human thing, a mammal thing, a living being thing? Like, do we just - is movement just inherent?

FREIWALD: It must be. I mean, I don't know if you can always know what people's motivations are. But if we think about, we can go way back in deep time that all of us - all of our families have a migration story, one that we don't think about because humans actually originated in Africa. And at some point, they started to move following - maybe following the animals they hunted, maybe out of curiosity. We don't know. But pretty soon they're moving into the Middle East. Some people went over to Asia. Some moved up into Europe. And over thousands of thousands of years, they got to the Americas. We've even got to Antarctica now. And people are talking about the moon and Mars.

(SOUNDBITE OF MUSIC)

FREIWALD: When I think of migrant, I think about what the people say about, why did you move? And if you look, for example, at the migrants in Africa trying to come to Europe, some of them talk about this thing like a hunger. But they don't mean they're hungry. They mean it's a hunger. It's a hope. They want to see, you know, what's better, what's life. It's a curiosity. It's an adventure. These are the modern-day explorers. I don't think of Christopher Columbus. I think of the people today who are taking the risk of going. Maybe it's across an ocean; maybe it's across a river, across a small road, or maybe it's just a community that's new that's only 10 miles away from where they grew up. These are the people who are - I think of when I think of migrants.

(SOUNDBITE OF MUSIC)

ZOMORODI: That's Carolyn Freiwald. She's a bioarchaeologist, and you can see her full talk at ted.com. On the show today, ideas about the search for a place to call home. I'm Manoush Zomorodi, and you're listening to the TED Radio Hour from NPR. Stay with us.

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