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Genetic analysis has shed light on the long-standing mystery surrounding the fate of President George Washington’s younger brother Samuel and his relatives. Two of Samuel’s descendants and their mother were recently identified from skeletal remains found in unmarked graves dating from the 1880s. The investigation also yielded the first patrilineal DNA map for the first US president to have no children of his own.
The researchers pinpointed key ancestral details through several types of DNA analysis, including a new technique that analyzes tens of thousands of genomic data to find so-called single nucleotide polymorphisms, or SNPs, which are variations in the genetic sequence affecting a single nucleotide in the genetic sequence. DNA.
Another important component was DNA from Samuel Washington’s living descendants. By comparing intact DNA from descendants with degraded, centuries-old DNA in bone fragments, scientists uncovered clues about long-lost identities and connections in the Washington family, researchers reported Thursday in the journal iScience.
“The multitude of these methods allowed us to uncover relationships between unidentified human remains from the mid-19th century and a descendant who lived several generations removed from their ancestors,” said senior study author Charla Marshall, a molecular anthropologist and deputy director of the research center. U.S. Department of Defense DNA Operations, in an email.
According to the research, these techniques, II. It may also help identify unknown remains of people who served in the military dating back to World War II.
Buried in unmarked graves
Samuel Washington, two years younger than George, died in 1781 and was buried in the cemetery at the Harewood estate near Charles Town, West Virginia. Records show there were 20 members of the Washington family at the Harewood cemetery, “including Samuel Washington and his two wives, their children, grandchildren and great-grandchildren,” said Courtney L. Cavagnino, a research scientist and research scientist. US Armed Forces DNA Identification Laboratory.
But unlike George Washington, who is buried in a magnificent marble tomb in Mount Vernon, Virginia, Samuel’s grave is unmarked, presumably protected from grave robbers, Cavagnino said in an email to CNN. Other graves also lacked headstones, leaving modern historians uncertain about who was buried where.
Researchers dug five unmarked graves at the cemetery in 1999 in an attempt to find Samuel Washington’s resting place. Small bones and teeth were recovered from three graves, but DNA tests at the time were inconclusive; The samples were severely degraded and contaminated with bacteria.
Fortunately for the authors of the new study, “DNA analysis has come a long way since the early 2000s,” Cavagnino said. They combined techniques that optimized shortened strands of damaged DNA from the remains, allowing them to extract the genetic material they needed. Maternal relationships were determined through mitochondrial DNA sequencing, while paternal relationships were found by looking at Y chromosomes. More detail came from 95,000 SNPs, an enormous amount of data targeting autosomal DNA (DNA not linked to sex chromosomes).
Genetic data first revealed that the remains belonged to a woman and her two sons; Records also clarified that the woman was Lucinda “Lucy” Payne and that the men were Samuel’s grandchildren (and George’s grandchildren): George Steptoe Washington Jr. and Dr. Samuel Walter Washington. DNA of living descendants of Dr. It was closer to Samuel Walter Washington’s DNA.
Scientists said that these data not only prove that the deceased doctor was the great-great-grandfather of the living Washington, but also show which remains belong to which brother, otherwise it would be impossible to establish this with certainty.
Recovered identities
In 1882, the remains of several individuals were exhumed from Harewood and moved to graves at Zion Episcopal Church in Charles Town. Among them were Lucy Payne and her sons. However, some of his bones were left behind; It was not clear who they belonged to when the 1999 excavation uncovered them. Now, nearly 150 years later, these remains have finally been identified.
“The combination of deceased and living relatives made this study a wonderful puzzle that you had to work hard to solve, but you had all the necessary pieces,” said Connie J. Mulligan, professor of anthropology and anthropology coordinator. University of Florida Genetics and Genomics Master’s Program. Mulligan, who studies genetic variations to understand how DNA shapes health and disease, was not involved in the research.
It turns out that the living grandson Samuel Walter Washington, the current owner of the Harewood estate, has more DNA in common with the two deceased brothers than researchers expected. They attributed this to family tree collapse caused by multiple cousin marriages in the Washington family tree, where marriages between relatives reduce the number of ancestors.
“Mutual cousin marriages only affected the kinship relationships of siblings, not those of mothers who married into the family,” Mulligan told CNN. “I don’t know of any other study that has as great a data set as this that covers the complexity in genealogy, so you can use empirical data to test how mutualism changes estimates of kinship.” He added that the investigation “is a combination of cutting-edge science and excellent detective work.”
Because the male individuals in the study (living and deceased) “were all direct paternal descendants of George Washington’s father, Augustine Washington,” the researchers’ analysis also revealed the first Y-chromosomal DNA profile for George Washington, Marshall said. This profile could clarify genealogical relationships among people who inherited the Washington surname but are unsure of their familial connections “to determine who is paternally related to George Washington,” the study’s authors wrote.
But while the findings offer many new insights, the question that launched the 1999 excavation remains: Where is George’s brother buried? According to Marshall, Samuel’s tomb has not yet been discovered and any of his remains have not been identified. At this point, he added, his location may have been completely lost.
“The search for Samuel Washington’s grave is no longer ongoing,” Marshall said. “It is possible that his grave was dug a long time ago and was never found again.”
Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American, and How It Works magazines.
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