1.3 million people share DNA with Maryland’s earliest colonists
In 1634, English settlers established St. Mary’s City as the first permanent outpost of the Maryland colony. Many of these early residents were eventually buried in Chapel Field Cemetery, including 49 settlers between the town’s founding and 1734. Recently, geneticists collaborating between Harvard University, the Smithsonian Institute, and the genetics company 23AndMe analyzed these previously unidentified remains as part of a larger genealogical project tracing colonial migration across the United States.
Their findings illustrate how such a small original population can have broad genetic influences over time. According to the team’s study published in the journal Current biologymore than 1.3 million living descendants can be traced directly to the handful of settlers buried at St. Mary’s City. Additionally, researchers believe they have potentially identified remains belonging to Maryland’s second governor.
The results come after decades of work that began with the excavation of a trio of extremely rare lead coffins in the cemetery’s brick chapel in 1986. They were later found to contain the bodies of Philip Calvert, his first wife Anne Wolseley Calvert and an infant son of Calvert’s second wife, Jane Sewell. Calvert served as the fifth governor of Maryland and came from one of the colony’s most prominent and influential founding families. Subsequent DNA analysis linked the Calverts to three other bodies buried nearby.
“Although further work is needed to determine exactly how these individuals were related to Philip, this discovery is significant given that several members of the extended Calvert family, including Philip’s half-brothers Leonard (1610-1647) and George (1613-1634), died at St. Mary’s during this period,” explained Douglas Owsley, Smithsonian curator of biological anthropology.
Further genetic testing identified relatives among five other families, including one that spanned three generations.
“With mortality so high in the early days of the colony, finding a multigenerational family was a surprise,” Owsley said. “This is a discovery that simply would not have been possible without a genetic study.”
From there, the team was able to move forward through the centuries by comparing DNA information from St. Mary’s City with that of more than 11.5 million participants in the 23AndMe genetic database. The results show that there are now approximately 1.3 million living relatives of Maryland’s early European residents. They were also able to corroborate a major migration that occurred between 1780 and 1820, when many of the colony’s Catholics fled south to Kentucky due to economic stressors and anti-Catholic sentiments.
One of the most revolutionary aspects of the study involved the researchers’ ability to evaluate unknown remains through a combination of genetic material and multiple family trees including still-living individuals. First, they identified the people in the database who shared the strongest genetic relationships with the three associated cemetery bodies. They then looked at overlaps between anthropological information and known lineages to narrow down the mysterious remains. Based on their findings, the team now believes the remains belong to Maryland’s second colonial governor, Thomas Greene, his first wife, Anne, and their son, Leonard.
“This is the first time that ancient DNA has been used to help identify unknown individuals, without any prior knowledge of their identity. And it turns out that one of these individuals turned out to be one of the most prominent figures in colonial Maryland,” said Éadaoin Harney, senior scientist at the 23andMe Research Institute.
Study co-author and Harvard Medical School geneticist David Reich added that their latest work shows how analyzing ancient DNA can be vital to expanding our understanding of history.
“Although the written record is extraordinarily rich, genetic data can still fill in gaps in these records and produce surprises,” Reich said.
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