Genomes from enslaved Africans who were freed and died on a remote Atlantic island in the mid-nineteenth century are offering clues about their origins in Africa. The findings come from the largest study of genome data obtained from remains of enslaved people and offer insights into the transatlantic slave trade, in which an estimated 12 million Africans were kidnapped and enslaved in North and South America and the Caribbean.

Researchers analysed the DNA of 20 people from the British island territory of St Helena, who the British Navy had liberated and brought there. The research, posted on the BioRxiv preprint server last month ¹ , suggests that the people might have been captured in parts of west-central Africa, including present-day Angola and Gabon.

Pinpointing the precise origins of people trafficked in the transatlantic slave trade is not yet possible, largely because of gaps in genome databases of people living in Africa today. But researchers say that genetic studies such as this can offer insights into the history of people who were previously known mainly through shipping logs and other commercial records.

No island paradise

St Helena, which lies in the Atlantic Ocean nearly 2,000 kilometres west of Angola, occupies a unique chapter in the history of the transatlantic trade in people. After Britain outlawed the slave trade in 1807, its navy intercepted slave ships and sent an estimated 24,000 people to St Helena (see ‘The route to Rupert’s Valley’). They had been aboard ships heading largely to Brazil and Cuba between 1840 and the late 1860s.

Many of the people freed arrived in poor health and were housed in squalid conditions in an isolated coastal valley, and as many as 10,000 died on the island. In 2006, construction work for St Helena’s first airport uncovered mass burials. Archaeologists unearthed the remains of 325 people — more than half under 18 and many younger than 12.

Unlike cemeteries in the Americas, which tend to hold multiple generations of people who had once been enslaved, nearly all of the people who died on St Helena were likely to have been born in Africa.

Shipping records — the primary historical source on the African origins of people taken into captivity — tend to record only the ports where slave ships embarked, but other records suggest that many of the people were captured further inland.

To attempt to better trace the Africans who were left on St Helena, a team led by palaeogenomicist Marcela Sandoval-Velasco and ancient-DNA researcher Hannes Schroeder, both at the University of Copenhagen, tested remains from 63 of the people who had lived on St Helena for intact DNA. They managed to sequence partial genomes from 20.

Seventeen were male — backing up records indicating that, in its final decades, the transatlantic slave trade captured far more men than women. Analysis of the genome data found that none of the people were closely related, nor did they belong to a single African population.

Comparisons with genome data from thousands of modern Africans from dozens of populations suggest that the people from St Helena are most closely related to people living today in central Gabon and northern Angola. But the researchers caution that gaps in present-day genome data from potential homelands, such as the Democratic Republic of the Congo, make it difficult to say for certain where the people buried in St Helena were taken from.

“Although it’s very hard to exactly pinpoint their origins, I think what we see in our results is that they are not coming from a single population,” says Sandoval-Velasco.

This insight suggests that the liberated Africans taken to St Helena lived in a challenging multicultural setting where they might not have understood the language and customs of others left on the island. “We hope that by illustrating the history and the condition of a few, we are at the same time illustrating the condition of the many, but it shouldn’t stop there,” Sandoval-Velasco says.

Individual stories

Ancient-genome analysis is a powerful tool for shining a light on people exploited in one of history’s darkest chapters, says Rosa Fregel, a population geneticist at the University of La Laguna in the Canary Islands, who was not involved in the St Helena study. “Usually it’s just about numbers — how many people from each country. Here, we are talking about particular people and their origin,” says Fregel, who is applying ancient genomics to illuminate the histories of people captured in the Indian Ocean slave trade. “Ancient DNA has the potential to tell their story.”

The data lay a solid foundation for studies that could pinpoint the specific regions that the liberated people were from, says Fatimah Jackson, a biological anthropologist at Howard University in Washington DC. The key to identifying the origins of enslaved people, she says, will be expanding data sets of modern Africans, as well as sequencing more remains. She and her colleagues have skeletal material from all 325 people that were recovered from the St Helena burial and hope to generate genome data soon.

David Eltis, a historian at Emory University in Atlanta, Georgia who co-founded a database that collects information on 36,000 slaving voyages between 1514 and 1866, notes that most people captured in the transatlantic slave trade originated from south of the equator — where a paucity of genome data from modern inhabitants makes it difficult to trace the origins of enslaved individuals with any accuracy.

Reburial plan

Although working with human remains can be ethically fraught, particularly when there are no known direct descendants to consult, the work can have value when carried out with sensitivity, says Jada Benn Torres, an anthropologist at Vanderbilt University in Memphis, Tennessee. (Several hundred of the liberated Africans later integrated into St Helena’s population, but it is not clear if they left any descendants.) Studies like this add another layer to the historical record, bringing to life the moving personal stories behind the slave trade, she says.

“You don’t often hear about those who didn’t make it — usually the story ends with their death,” says Benn Torres. “This provides a perspective on those who weren’t able to make it home. This is important for the world to learn from.”

Remains of the 325 liberated Africans that were excavated are in storage on St Helena. In 2018, the territory’s government endorsed plans to rebury them in the valley where they were first uncovered and to create a memorial at the site.