How teeth are uncovering the origins of enslaved Africans

**SPEAKER_1** (0:00)
Support for Here & Now Anytime comes from MathWorks, creator of MATLAB and Simulink software, to design and develop engineered systems, accelerating the pace of discovery in engineering and science. Learn more at mathworks.com.

**Carly Strange** (0:16)
WBUR Podcasts, Boston.

**Anina Faneil** (0:21)
It was very much a reconnection to myself, a claiming back of identities that I had lost in the sense of my Africaness, my blackness, my humaness.

**Chris Bentley** (0:33)
Workers on a remote island in the South Atlantic Ocean discovered the remains of thousands of people kidnapped from Africa in the transatlantic slave trade. Now, they're bringing them home.
It's Friday, August 7th, and this is Here & Now Anytime from NPR and WBUR. I'm Chris Bentley. A little later on the show, is the cure for loneliness rolling a 12-sided die?

**Greg Billsland** (1:08)
D&D has this magical effect at creating cohesion, camaraderie and friendship.

**Chris Bentley** (1:14)
Here's some level 20 analysis of how Dungeons & Dragons is balancing big business with its small d democratic origins coming up in about 15 minutes.
But first, new science is reconnecting long-lost lines of genealogy that were severed by the slave trade. Europeans enslaved more than 12 million Africans over hundreds of years, packing them onto ships, and selling them into bondage across the Caribbean and the Americas. Britain officially abolished the slave trade in 1807, but its navy continued to intercept slave ships coming from Africa for decades. It quarantined some of the people on those ships on the remote island of St. Helena, a British overseas territory in the South Atlantic.
Thousands died in settlements with poor conditions on that island, and they were buried in mass graves, mostly forgotten for centuries, until workers building St. Helena's first airport in the 2000s unearthed their bones. In a few minutes, we're going to hear from someone who has devoted herself to repatriating those remains. But now we're going to hear from Hannes Schroeder, an archaeologist at the University of Copenhagen. He led a study just out in the journal Science that traced the origins of the people buried in St. Helena using their teeth. He spoke to Scott Tong.

**Hannes Schroeder** (2:41)
In this case, we used isotope analysis, actually a combination of isotopic analysis and ancient DNA analysis. So an isotope is essentially just a different version of an element, to put it very simply. Isotopes vary in a landscape based on geology, for example, and then we, through the food and water, we tend to absorb these isotopes. And so you can measure those, and then you can relate those back to the geology, and that's in essence how it works.

**Scott Tong** (3:14)
Then you examine the teeth for the isotopes, and that's where the interesting part begins as far as tracing back to location.

**Hannes Schroeder** (3:21)
That's right, because basically the teeth pick up the signature, if you want, of the place where people grew up. So then you can measure those in archaeological remains and you can relate those back to the geological measurements.

**Scott Tong** (3:35)
Hearing you talk about the science, it just sounds amazing, right? Because these human remains, centuries old, and here the science has arrived to answer some of these questions. Is this brand new science? I understand it took 10 years to publish these results. Were you kind of along the way waiting for the science to develop?

**Hannes Schroeder** (3:54)
I mean, so isotope analysis have been around for a while.
It's fairly easy to establish whether somebody didn't grow up in the place where they were buried, but it's much harder to try and establish where they had actually come from. And there have been some developments here in the field, and that's the use of these isoscapes. So that's a fancy term to basically say variations of isotopes or isotopic ratios across a landscape, right? So imagine a map that basically maps out this isotopic variation. And because we have those now four places, like Sub-Saharan Africa in this case, we can use those maps and then relate them to the measurements that we make. And we can, based on those comparisons, essentially, we can come up with estimates as to where people most likely would have come from.

**Scott Tong** (4:42)
So then coming to these remains found on St. Helena, what did you learn about where some of these persons came from? How accurate could you get?

**Hannes Schroeder** (4:54)
Yeah, and of course, I mean, up front, we should definitely say that we're dealing with probabilities here, right? We're not able to pinpoint a specific village or anything like that. But really, what we can see was that these individuals came from many different parts of Africa. The vast majority came from places now in Angola and the Republic of Congo, so parts of essentially coastal areas of West Central Africa. But what was surprising is that a significant number of the individuals we analyzed came from much further inland, so hundreds, not thousands of kilometers.