Posted on 09/23/2026 12:48:56 AM PDT by woodpusher
BioRxiv
The Preprint Server for Biology
The DNA Legacy of Thomas Jefferson
Posted September 21, 2026
Richard E. Green, Samuel H. Vohr, Joshua D Kapp, Jane E. Ailes, Samuel Sacco, Remy Nguyen, James Cahill, Peter D. Heintzman, Joanne Flores, Logan Kistler, Courtney A. Hofman, Robert C. Fleischer, Beth Shapiro, Richard Kurin
doi: https://doi.org/10.64898/2026.09.18.752809
This article is a preprint and has not been certified by peer review [what does this mean?].
Abstract
Allegations that Thomas Jefferson fathered the children of the enslaved Sally Hemings emerged in the context of U.S. presidential politics in the late 1700s and early 1800s and entailed strongly contested denials and affirmations by family members, biographers, and historians ever since. Previous analysis of Y chromosome markers in contemporary members of the Jefferson and Hemings patrilines was consistent with the paternity hypothesis but rejected by those who pointed out that, absent Jefferson DNA and its direct comparison to the DNA of possible descendants, other Jefferson males could have fathered Sally Hemings children. In this study, we developed an innovative technique to recover DNA from multiple rootless hair samples in a museum collection whose provenance, mitochondrial genomes, Y chromosome markers, and identity to each other indicate that these hairs and the DNA from them are from Thomas Jefferson. Using these DNA data, we find clear evidence of Thomas Jefferson ancestry in descendants of both his wife Martha Wayles Jefferson and Sally Hemings. We measured the amount of identical-by-descent DNA shared between Thomas Jefferson and his known and putative descendants. We find that the amount of shared Jefferson DNA is more likely under the model of direct Thomas Jefferson paternity than other proposed scenarios.
Competing Interest Statement
REG is co-founder and paid consultant of Astrea Forensics. SHV is employed by Embark Veterinary, Inc. BS is the chief science officer of Colossal Biosciences.
Funder Information Declared
The Smithsonian provided its own trust funds to support the research.
Copyright
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC 4.0 International license. https://www.biorxiv.org/content/10.64898/2026.09.18.752809v1.full.pdf
Full report, 18 pp.
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This is brand new science where the full DNA profile of Thomas Jefferson was revealed using deathbed hair clippings without follicles, something previously impossible to do. The scientific method has been accepted in court.
The new science used has been accepted in court for admission of criminal evidence. You almost have to expend the effort to read about what was done to understand what was done.
Yeah, I know this is a new DNA analysis separated from previous ones some years ago.
It is very new, but old enough to have been accepted in court to determine admissible evidence in a murder trial. It is about what new science reveals using hair without follicles. The Richard Green cited inn the Gilgo Beach murder case is also the first named author of the paper submitted to bioRxiv.
https://www.liherald.com/stories/gilgo-dna-evidence-allowed,217179
Hair DNA evidence deemed admissible in Gilgo Beach murder trial
Posted September 3, 2025
In September 2025, Suffolk County Supreme Court Judge Tim Mazzei ruled that Astrea Forensics’ whole genome sequencing method — which extracts SNP data from rootless hairs and creates DNA profiles — is “generally accepted as reliable within the scientific community”. This was the first time such technology was admitted in a New York state court, setting a potential precedent. The judge’s decision relied on expert testimony from University of Washington professor Kelley Harris and Astrea Labs founder Richard Green, and no defense expert contested the method’s reliability.
In practical terms, it means nobody else with proven expertise in the field has yet challenged the assumptions in this article.
It has not been peer reviewed by referees. The scientific method has been found by a court to be “generally accepted as reliable within the scientific community” and used for the admission of evidence in a murder trial.
Now do Bill Clinton.
so what?
This is the 4th thread about this and am amazed at the amount of attention they get, and the reason for that attention. who really gives a rats ass if some famous white dude was tappin a black broad 200 years ago!??
You people need to get a life!!
It carries on because there is no proof ruling out other men.
i don’t think the DNA ruled out Thomas; but it didn’t rule out a bunch of other possibiiities.
It carries on because of irrational biases.
Show us the proof.
The proof is in this study. There is zero evidence for any other view.
‘more likely’ is not proof. It’s just an assumption informed, yes, by predetermined ‘biases’.
This is the 4th thread about this
I am unaware of the other three threads about the new scientific method and its application, the topic of a book and a scientific paper from 9/22/2026.
It carries on because there is no proof ruling out other men.
It carries on because the new scientific method significantly distinguishes the probability of Thomas Jefferson paternity.
From submitted paper:
Finally, we estimated joint likelihood ratios and posterior probabilities under the assumption that Eston and Madison Hemings had the same father (Table 2). Under this assumption, we estimate that TJ paternity is 2,213 (1,614–2,814 central 95th percentile interval) times more likely than RJ paternity using the 5 cM threshold and 3,672 (2,811–4,559) times more likely using the 10 cM threshold. We obtained similar posterior probabilities (~99.95%) from both thresholds. When we allow for Eston and Madison Hemings to have different fathers and use a uniform prior where all combinations of paternity are equally probable, we estimate the posterior probability of TJ paternity for both Eston and Madison to be 82.4% (81.73%–82.9%) and 86.4% (86.09%–86.57%) using the 5 and 10 cM thresholds, respectively, and obtain a posterior probability of ~99.96% that Thomas Jefferson was the father of a least one of Eston and Madison (SI, Tables S8 & S9) and therefore a posterior probability <0.1% that he was not the father of either one.
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