Forty-nine people buried in Maryland’s first colonial capital now have genetic connections stretching across the modern United States. Researchers matched DNA recovered from their remains with segments carried by more than 1.3 million living research participants. The same analysis traced migrations, reconstructed families and offered possible names for previously unidentified graves.
St. Mary’s City supplied a founding population
English settlers established St. Mary’s City in 1634 as the first permanent settlement and capital of the Maryland colony. Its Chapel Field cemetery contains residents from the colony’s earliest generations, including prominent families, laborers, servants and people whose legal status remains uncertain.
For a study published in Current Biology, researchers generated genome-wide data from 49 people buried there during the seventeenth and early eighteenth centuries. The international team included scientists connected with the 23andMe Research Institute, Harvard Medical School, the Smithsonian and Historic St. Mary’s City.
Recovering usable genetic material required protocols designed for old, degraded DNA. Researchers sampled skeletal tissue, screened for contamination and authenticated characteristic damage patterns before comparing the resulting genomes. Archaeological context remained essential because a genetic profile alone cannot establish when a person lived, where a burial sat or what objects accompanied it.
Shared DNA segments linked past and present
The analysis used identity-by-descent, or IBD, segments. These are stretches of DNA shared because two people inherited them from a common ancestor. Longer and more numerous segments usually indicate a closer relationship, while short segments can connect distant branches separated by many generations.
Researchers compared the ancient genomes with data from more than 11.5 million consenting participants in the 23andMe research database. They identified over 1.3 million participants who shared detectable genetic connections with at least one St. Mary’s individual. The number is an observed count inside that database, not an estimate of every descendant alive worldwide.
The Smithsonian Research record confirms the study’s authorship and DOI, tying the result to decades of archaeological and biological-anthropology work at the site. The scale became possible because a large modern comparison set can detect patterns that no single family tree could reveal.
Western Britain and Kentucky emerged from the map
Genetic sharing with modern participants pointed strongly toward western England and Wales, supporting those regions as important origins for many of the settlement’s early European residents. That result adds biological evidence to passenger lists, court documents and other colonial records.
A second cluster appeared among participants with roots in Kentucky. Historical accounts describe Maryland Catholics moving south and west after the American Revolution, particularly between about 1780 and 1820. The genetic pattern independently recovers that movement, showing how descendants of a small founding population spread while retaining detectable segments from common ancestors.
Founder effects help explain the reach. A limited number of people contribute ancestry to a growing population; across many generations, their descendants can number in the hundreds of thousands or millions. Recombination breaks inherited chromosomes into smaller pieces each generation, but a sufficiently large database can still find matching fragments.
Genetics proposed names for unknown graves
The team combined close IBD matches with family trees, burial context and historical records to suggest identities for three people. One possible identification is Thomas Greene, Maryland’s second colonial governor, along with his first wife, Anne, and a son named Leonard. The wording remains cautious because a genetic match must fit documentary and archaeological evidence before it becomes a historical identification.
An institutional research release also describes links among families buried near the brick chapel and the published genomes of the Calvert family. The work revealed a multigenerational family at a time when high mortality often broke households apart, as well as individuals whose ancestry and skeletal evidence complicate a simple story focused only on colonial elites.
The database provides power and boundaries
The 1.3 million figure depends on who joined the research cohort and consented to analysis. Participation is not evenly distributed across populations, and distant relatives may carry segments too small to meet detection thresholds. The true number of living descendants or relatives is therefore not identical to the number the study connected genetically.
“Genetic relative” is also broader than a direct descendant. Two people can share DNA because both inherited a segment from an earlier common ancestor, even if neither descends from the other. Across nearly four centuries, overlapping family lines make the network wide and complex. The study’s count describes detected biological connections, not 1.3 million people assigned to one simple pedigree.
Ancient DNA also raises ethical questions because deceased people cannot consent and historical communities may have different interests in how remains are studied. The project’s value rests partly on transparent methods, respectful archaeological stewardship and careful separation between a probable identity and a proven one. The David Reich Lab publication record makes the article, supplementary material, DOI and new genotype resources available for scrutiny.
The result demonstrates what historical genetics can add even where written archives are unusually rich. Documents describe offices, property and migration, while DNA can expose unrecorded relationships and connect a cemetery to living populations at enormous scale. Forty-nine graves became anchors in a network of more than 1.3 million identified genetic relatives, bringing individual bodies, colonial families and centuries of movement into the same evidence base.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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