The Lost Descendants of Thomas Jefferson

America’s longest-running paternity dispute has seemingly come to an end: Thomas Jefferson fathered children with Sally Hemings, his enslaved chambermaid, and the Smithsonian has the DNA to prove it. Richard Kurin, a fifty-year veteran of the institution, launched a top-secret study of the question in 2011. Starting with a few hair samples, he and a team of scientists sequenced Jefferson’s genome and compared it with those of Hemings’s descendants, after a sprawling effort that involved everything from compiling genealogies to scouring rural Virginia for a lost grave. The project’s thoroughness would be almost comical were its subject not so stubbornly controversial, an emblem of all the contradictions embedded in who, exactly, Americans take themselves to be.

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“My ideal was for people to make a decision ‘on the papers,’ ” Gordon-Reed told me, using a legal term for a decision reached solely on the basis of written testimony. Her book won both a Pulitzer Prize and a National Book Award, and Monticello dedicated an exhibition to Sally Hemings, declaring the matter settled. Still, doubts remained. A few skeptics theorized that the President’s brother might have impregnated Hemings. In the nineties, Gordon-Reed called this the doctrine of “any Jefferson but Thomas,” predicting that for some diehards—who dismissed Black sources while naïvely crediting white ones—no proof would ever be enough.

Kurin’s research faced criticism even before its official release. Last week, The Chronicle of Higher Education published an interview with a Hemings descendant who pulled out of the study. She disapproved of Kurin’s decision to publish a commercial book about his findings before a scientific paper, and had a “gut” feeling that Jefferson couldn’t be her ancestor. Yet the Smithsonian remains confident. The paper has been peer reviewed and is being cleared for publication at Proceedings of the National Academy of Sciences (PNAS), and has also been vetted by a trio of leading genomic scientists. (A preprint of the paper will be released tomorrow, along with Kurin’s book.) “Now you can’t think about the founding without thinking about Black people,” Gordon-Reed said. The study shouldn’t have been necessary, but she’s happy to see her scholarship vindicated: “You have to do overkill with these things.”

Kurin’s study began with a stray thought. An anthropologist by training, rather than a scientist or a historian, he had been reviewing a Smithsonian documentary about the Jefferson Bible when it occurred to him that the President might have shed or bled on the volume. Sure enough, conservators had found hair in its pages, which Kurin quietly sent to labs across the country. Sequencing a genome from old, rootless hair was once impossible, because the DNA within them has broken into very short segments. “Imagine having a jigsaw puzzle with three billion pieces, and you need to figure out the edges,” Kurin explained. (Another common challenge is contamination with bacterial DNA.) But two ancient-DNA specialists, Richard Green and Beth Shapiro, agreed to look into the problem. They set about distilling as much Jefferson as they could.

The idea was to bypass the uncertainties of the Foster study by going to the source. If Thomas Jefferson’s genome could be sequenced, it would then be possible to calculate Hemings descendants’ “identity by descent” (I.B.D.) from Jefferson, without having to rely on genetic markers that he might have shared with, say, his brother Randolph. But the experiment was fraught with difficulties, as Kurin’s book, “History by a Hair,” makes clear. After a years-long effort to extract just a fraction of DNA, the Bible hairs turned out not to be Jefferson’s. Luckily, Monticello had provided other clippings from his deathbed. These were authentic—but, after so many generations of semi-random recombination, not all of the Hemings descendants had enough genetic overlap with Thomas to definitively rule out Randolph.

So Kurin decided to exhume him. With DNA from Randolph’s remains, the team could determine which Jefferson each descendant had more I.B.D. with, and, thus, which was their forebear. Yet the location of Randolph’s grave had been lost to time. Kurin conducted an archeological survey of the area where his plantation once stood, assisted by a biographer, a “bone hunter,” experts in forensics and lidar, and an authority on historic buildings. After a search of thirteen-hundred acres, they found little more than a few old bricks and nails.

The project might have ended there had Kurin not made contact with a few previously untested Hemings descendants. One of them shared over five per cent of her DNA with Thomas Jefferson—not just enough to establish that he, specifically, was her ancestor but more than any of those tested from his legitimate family. Meanwhile, there were breakthroughs in California. Green and Shapiro’s lab at U. C. Santa Cruz had devised a new way to extract and prepare old DNA, which enabled them to sequence Jefferson’s entire genome. Their new method was also key to the conviction of the Gilgo Beach serial killer, as well as the recent “resurrections” of extinct species by Colossal Biosciences, where Shapiro is the chief scientist. And the discovery will likely beget still others. “We hope to post the Jefferson genome online and make it accessible,” Kurin told me. It could lead to the identification of Sally Hemings’s other children, who left the family and passed for white.

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