Crystal Emory never knew much about where she came from. Family members took her from her mother for being in an interracial marriage in 1960s and 1970s, leaving her floating between homes. She spent time in an orphanage in Pennsylvania. These experiences, she says, helped instill a need to find out more about her history.

"I just always wanted to know who my family was, and more about myself," says Emory, 68, now retired from a career in IT. "I just started doing genealogy."

She knew grandparents were Black, but not much else. She looked for names in newspaper articles, and collected what family lore she could.

"My father's mother would tell me stories about the family, and I was writing these stories down as a young person," she said.

It wasn't until the Smithsonian Institution and a historical society in Frederick County, Md. came calling that Emory was able to trace her history to the Catoctin Furnace, a small ironworking village that made utensils and ammunition for the U.S. from the late 1700s to the early 1900s. With the help of diaries and other records, they connected her to a free, land-owning Black man named Robert Patterson who lived in the area through much of the 19th century. Thanks to that, Emory was able to learn a little about the life he led.

"He owned property before the Civil War," she said. "He was productive in the community, helping to build a school."

Like Emory, Black Americans across the U.S. are missing significant parts of their ancestry. But for many of them, such written records directly linking them to the past are rare. Some can trace the threads of their lineage back to the 1870 census – the first count of the U.S. population that included all Black people. But beyond that, those threads typically end – severed by centuries of slavery, during which families were split by slave owners and traders who did not record familial connections.

Now researchers are taking a closer look at the Catoctin Furnace, using the DNA of forgotten enslaved and free workers there to tie them to people in the present. The research, published in the journal Science, taps into biotech company 23andMe's database of genetic information from millions of direct-to-consumer ancestry tests. It opens a new kind of historical gateway for Black Americans, one that could help many others across the United States find out more about their heritage – and their relationships to one another.

"This work represents a step forward for enabling further study of the biogeographic origins and genetic legacy of historical African American populations, particularly in cases where documentation is limited, as is common," says Henry Louis Gates Jr., director of the Hutchins Center for African & African American Research at Harvard University and an author of the study.

Unearthing genetic connections

In 1979, a previously unknown cemetery at Catoctin Furnace was found and excavated as the state worked on a highway in the area. The unmarked bodies were put in the care of the Smithsonian. Now, with more advanced methods of collecting ancient DNA, the Catoctin Furnace Historical Society, the Smithsonian, Harvard University and the biotech company 23andMe have connected 27 of those bodies to nearly 42,000 people from the present-day who are related in some way to the people buried there – and to each other.

Further DNA analysis was able to hone down the 42,000 people to a list of closer relatives.

"There was a smaller subset of just under 3,000 people who share a particularly strong genetic connection to the Catoctin individuals, and we call these individuals the closest relatives," says study author Éadaoin Harney, a population geneticist at 23andMe.

Those individuals could range from five to nine degrees of separation, covering a wide range of relationships from great-great-great-grandchild to a first cousin six times removed.

The DNA also revealed clues about the lives the people buried there led.

"We're able to restore some of the information about the lives of the Catoctin individuals," Harney said. "We highlight the family members that they have who are also buried in the cemetery. We also are able to discuss some of the health issues that they might have suffered from like sickle cell anemia, and also talk about their ancestral origins."

There are still mysteries about who may be related to those people found at Catoctin Furnace.

"We don't have any idea who these people were, because they're anonymous within the cemetery," said Elizabeth Comer, the president of the Catoctin Furnace Historical Society and a study author. "We have put together, using our genealogical research and our historical documentary research, a list of 271 names of enslaved individuals who worked at the furnace. But we are unable, at this point, to connect those names to an individual in the cemetery."

The research does, however, allow scientists to aggregate data that points to where the Catoctin residents' ancestors once lived, giving anthropologists an idea of where in Africa they were taken from.

"You can tie people to specific regions in Africa such as Senegambia and west central Africa," says Douglas Owsley, a curator at the division of biological anthropology at the Smithsonian Institution and one of the study authors. "And then in Europe, some individuals have a considerable amount of European ancestry."

'A blueprint for future studies'

Fatimah L. C. Jackson, a biologist and anthropologist at Howard University who was not involved in the study, said the work was groundbreaking not just in its findings, but in its makings.

"What makes the work of Harney et al. so pioneering is that the research was initiated by an engaged local community of African Americans and results were structured to meet the needs, priorities, and sensibilities of the larger African American community," she wrote in a perspective article that accompanied the paper in Science. "This is the way that this type of research should be performed, and it provides a blueprint for future studies."

The Smithsonian, Harvard and the historical society have yet to contact any of the nearly 3,000 people out in the world who are closer relatives to the people buried at the Furnace.

Comer says she hopes that they can finally be tracked down.

"That history has been obfuscated, it's been erased, it's been eliminated from our narrative," she said. "Our whole being is to reconnect with a descendant community, both collectively and directly."

Comer says she hopes the descendants can form a society, much like the descendants of the Mayflower have, to stay in touch and build a community.