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George Washington Family Members Identified in DNA Analysis of Remains From Unmarked Graves

George Washington

NEW YORK – A team from the Armed Forces Medical Examiner System, SNA International, and elsewhere has identified family members of George Washington by genetically profiling ancient remains from unmarked burial sites and has determined the family's Y chromosome haplogroup.

The study followed from a late 1990s excavation effort at Harewood Cemetery in Charles Town, West Virginia, focused on finding an unmarked grave for George Washington's younger brother Samuel, who owned the Harewood estate. At the time, small bone fragments turned up at a handful of other unmarked graves, suspected of belonging to George Washington's great-nephews George Steptoe Washington Jr. and Samuel Walter Washington.

Although the remains of several family members were moved from Harewood to Zion Church in Charles Town in the late 1800s, fragmentary remains at the Harewood burial sites provided insights into their previous resting places.

For the latest study, appearing in the journal iScience on Thursday, researchers used targeted hybridization capture followed by sequencing to assess five mid-19th-century samples from three burial sites at Harewood Cemetery, focusing on the mitochondrial genome and nearly 95,000 SNPs from autosomal, X, and Y chromosomes.

"During the initial phase of the project, members of the Washington family provided a list of probable burials at Harewood containing information such as the name, date of birth, date of death, sex, age at death, and relationship," first and corresponding author Courtney Cavagnino, a research scientist with the Armed Forces Medical Examiner System's Armed Forces DNA Identification Laboratory at Dover Air Force Base, SNA International, and the Department of Defense DNA Operations, said in an email.

"It was suspected that 20 members of the Washington family were buried at Harewood including Samuel Washington and two of his wives, their children, grandchildren, and great-grandchildren, among others," Cavagnino said, adding that the "goal of this latest round of testing was to confirm the identities of the presumed individuals."

With the mitochondrial DNA data, for example, supported by autosomal SNA profiles, the researchers verified maternal relationships between individuals at burial sites on the property, including sibling and parent-child relationships anticipated from the historical information.

On the Y chromosome side, meanwhile, the team first compared SNP and short tandem repeat data from the newly profiled Y chromosomes with data from the FamilyTreeDNA consumer genetics database.

The investigators further refined their view of the inferred Washington Y chromosome haplogroup by bringing in Y chromosome data from a living descendent of George Washington's younger brothers, Samuel Washington and John Augustine Washington. The living participant was dubbed a "double Washington descendant," since his great-grandfather and great-grandmother were descended from different brothers of the former president.

"Our results reveal for the first time the inferred Y chromosomal haplogroup of President George Washington, which is of interest to genealogical research communities," senior author Charla Marshall, deputy director at DoD DNA Operations, who is also affiliated with the Armed Forces Medical Examiner System, SNA International, and Pennsylvania State University, said in an email. She further noted that "male individuals in the present study, living and deceased, were all direct paternal descendants of Augustine Washington, the father of George Washington."

The Washington lineage haplogroup, known as R-BY32422, appears to be quite rare in the FamilyTreeDNA database, Marshall explained. She noted that the company, which also participated in the study, plans to publish a related blog post and note on its website describing the Y haplogroup's historical connection.

More generally, Marshall said, the findings supported the veracity of the SNP-capture and extended kinship methods used for the study. Similar approaches are expected to be applied to remains of unknown military service members buried at sites such as the National Memorial Cemetery of the Pacific, which was used during the Korean War.

"SNPs will allow us to obtain a positive nuclear DNA identification for aged skeletal remains that have DNA too degraded for STR profiling," Marshall explained, adding that the team is "now validating these SNP methods, which were developed for ancient and historical DNA samples, in accordance with the quality assurance standards set forth by the FBI’s Scientific Working Group on DNA Analysis Methods (SWGDAM) as one of our accredited DNA testing methods."

"This case study highlights the benefits of a multi-marker approach for extended kindship prediction and DNA-assisted identification of historical remains when a reference sample from a living descendant is available," the authors wrote.