DNA helped solve the mystery of an old cemetery in Maryland
An old cemetery in St Mary's City in the US state of Maryland has helped scientists reconstruct part of the history of one of the first English colonies in North America. Researchers have studied the DNA of people buried here in the XVII-XVIII centuries and found genetic links with more than 1.3 million people alive today.
It's not about finding one specific ancestor for all these people. Scientists compared DNA fragments from ancient remains with data from the 23andMe research base and looked for signs of kinship - parts of the genome inherited from common ancestors.
This approach helped not only to understand where the first inhabitants of the colony came from, but also to trace how their descendants spread across the United States. In addition, the researchers suggested that among the unknown buried could be Thomas Green - the second governor of the colony of Maryland. But this is still a probable identification, not definitive proof.
Details
St Mary's City was founded in 1634 and was the first English settlement in the Maryland colony. For the new study, scientists took DNA from 49 people buried in Chapel Field Cemetery between 1634 and 1730. The work was published in the journal Current Biology.
This genetic data was then compared with data from more than 11.5 million members of the 23andMe research database. In this way, it was possible to find more than 1.3 million people alive today who have genetic links to those buried in St Mary's City. Most of the colony's ancient inhabitants turned out to be genetically closest to people from Britain, especially western England and Wales; some had an Irish connection.
DNA also helped clarify family ties within the cemetery itself. Among the remains studied were people from the famous Calvert family, which played an important role in the founding of Maryland. Three lead coffins had previously found Philip Calvert, his first wife Ann Wolseley Calvert, and an infant; genetic analyses revealed that the child was the son of Philip Calvert and his second wife Jane Sewell. In the new study, the authors found three more possible relatives of this family among the other burials.
Another important finding is a family traced back three generations. This is particularly interesting for an early colony: mortality rates were high, and such family chains are rarely seen from documents and archaeological finds alone.
The most "detective" part of the study has to do with the three unknown burials. The scientists identified people who were related to each other, then found contemporary 23andMe participants with the strongest genetic ties and asked them to share their family histories. By comparing DNA, genealogical trees and archaeological data, the researchers concluded that the most likely candidates were Thomas Green, his first wife Ann and their son Leonard.
Thomas Green was the second governor of the Maryland colony. The authors emphasise: the work is not yet complete and identities need to be confirmed further. But it was the genetic analysis that provided the clue that historians have been missing.
Why it's important
This study shows how DNA can complement written sources. Many documents have survived in the history of North America's early colonies, but they don't cover all the gaps: it's not always clear exactly who was buried, how people were connected, or where their families later moved.
Genetics helps us see what is not in the archives. In this case, it linked an old cemetery to modern people, showed family lines within the colony, and even reflected the migration of Catholics from Maryland to Kentucky between 1780 and 1820, known to historians. According to the authors, this genetic footprint coincided with a documented wave of migration associated with economic pressures and anti-Catholic sentiment in Maryland.
Background
St Marys City was one of the key settlements of Maryland's early colonial history. Colonists arrived there in 1634 on the ships Ark and Dove. Among the founders were members of the Calvert family: they are associated with the establishment of the colony, designed in part as a place of religious freedom for Catholics persecuted in England.
Archaeologists have long studied the site. Three rare lead coffins from the area of the old brick chapel have attracted particular attention. Their study went on for decades and eventually led to a collaboration between archaeologists, historians and geneticists.
The new work continues this lineage, but takes it a step further: it uses not only ancient DNA, but also a huge modern genetic base. By doing so, scientists have been able to connect the local history of one cemetery to the bigger picture - the origins of settlers, family ties, and the migrations of their descendants across the United States.
Source
Éadaoin Harney et al, "The genetic legacy of the 17th-century colonial capital of St. Mary's City," Current Biology, 2026. The publication analysed the genomes of 49 people buried in St. Mary's City between 1634 and 1730. Researchers matched ancient DNA with data from more than 11.5 million members of the 23andMe research database, found links to more than 1.3 million living genetic relatives, traced the origins of the colonists, and proposed the possible identification of three unknown buried individuals, including Thomas Greene.