DNA recovered from hair attributed to Thomas Jefferson adds new evidence to a family history long preserved by Sally Hemings’ descendants.

Jefferson, the third US president, enslaved Hemings at Monticello. Her family’s accounts identified him as the father of her children. A new, not yet peer-reviewed preprint compares his reconstructed genome with living descendants of his wife, Martha Wayles Jefferson, and of Hemings’ sons Madison and Eston.

The earlier DNA breakthrough came in 1998: Eston’s male line matched the Jefferson paternal line. That linked the families, but could not distinguish Thomas from other Jefferson men.

The new study uses hair preserved after Jefferson’s death in 1826. Collection history and several genetic checks support its identification. Shared inherited DNA connects the resulting genome to both family branches. One Madison-line descendant shares about 5.1% in the study’s initial analysis; that is one person’s estimated inherited sharing, not an ethnic ancestry percentage or a family-wide average.

The researchers then compare three possible fathers: Thomas, his brother Randolph, and a son of Randolph. For Madison’s branch, one model makes the observed DNA about 513 times more likely under Thomas’s paternity than Randolph’s. This is a likelihood ratio, not an ancestry percentage.

Eston’s branch also favors Thomas, but less strongly: about 5–7 times over Randolph. Under equal starting probabilities for the three tested models, Thomas’s estimated probability is about 99.8% for Madison and 83–87% for Eston. Those results depend on the models and assumptions.

The findings strengthen the case for descent from Jefferson himself. They do not genetically test the paternity of every child Hemings had, and they do not establish ancestry averages for Black or white Americans.

📚 Source: Green et al. (2026), bioRxiv (preprint)
The DNA legacy of Thomas Jefferson

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