Genetics of Individuals Buried at 17th Century Delaware Site Sheds Light on Colonial Demographics

Andrea Anderson

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 New genetic research is providing demographic insights into the early colonial settlement of the US East Coast — from ancestry that resembled populations in northwestern Europe to enslaved individuals from different parts of Africa.

Such results "are contributing to a growing body of evidence from colonial era sites in North America and the Caribbean about the impact of European entry into these regions and the incipience of the trans-Atlantic slave trade in these regions," Theodore Schurr, director of the University of Pennsylvania's Laboratory of Molecular Anthropology and consulting curator at the Penn Museum of Archaeology and Anthropology and one of the study's corresponding authors, explained in an email.

In an effort to get a glimpse at previously unknown colonial dynamics in an area that was less characterized than other regions, he and his colleagues used low-coverage, enrichment-based genome sequencing on bone samples from 11 individuals buried at a 17th century Delaware plantation known as Avery's Rest. They assessed these data alongside new mitochondrial DNA and Y chromosome sequences, and SNP data from efforts such as the Affymetrix Human Origins panel.

The team's results, published in Current Biology on Thursday, provided a look at the ancestry of eight European and three African individuals at the site.

"The data from this study provide an important reference point for other studies attempting to reconstruct the history of colonial sites in the Americas and their trade connections in the Atlantic world," Schurr said, "and elucidate the role that enslaved Africans played in the creation of new communities or settlements there."

Consistent with prior mitochondrial genetic and osteological analyses, the new sequence data suggested that the European representatives at the site had ancestry from Northwestern Europe, particularly populations in Britain and France. The European Avery's Rest group included members of a three-generation family with shared maternal roots.

On the other hand, the team found that the three individuals with African ancestry had more diverse ancestry from Barbados and West Africa, West-Central Africa, and Western and Eastern Africa, and included a father-child pair.

"While the European-descended individuals showed genetic affinities with contemporary populations from Northwest Europe, the three African individuals had genetic affinities with groups from different areas of Africa, consistent with what has been seen for ancient genomic analyses of African-descended individuals recovered from New World burial contexts," Schurr said.

The African individuals were also buried at a site that was roughly 15 to 20 feet from the European group, consistent with their suspected enslavement.

"The presence of these African individuals at Avery's Rest and the separate location of their burials relative to those of the European individuals indicates that their daily lives were governed by settler-colonial practices of racialized enslavement," Schurr explained.