DNA evidence from Thomas Jefferson’s hair reveals the truth about his relationship with Sally Hemings

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Opening a Bible that once belonged to Thomas Jefferson, staff at the Smithsonian National Museum of American History in 2011 discovered a reddish-blond hair pressed between the pages. That hair, suspected to have belonged to Jefferson himself, launched a DNA investigation spanning more than a decade that’s now providing a long-missing puzzle piece regarding Jefferson’s relationship with Sally Hemings, an enslaved woman in his household.

After spending years reconstructing DNA fragments, scientists have revealed the most compelling evidence to date that Jefferson, a founding father of the United States, also fathered children with Hemings — a relationship that has been long rumored but never definitively proven. How that investigation unfolded is documented in the book “ History by a Hair : Thomas Jefferson, Sally Hemings & Solving a 200-Year-Old Mystery,” written by Richard Kurin, a distinguished scholar and ambassador-at-large at the Smithsonian, and published on September 22.

Kurin is also senior author of a paper describing the methods that connected the former US president to Hemings’ descendants, which involved delving deep into the genetics of the Jefferson and Hemings family trees. The paper, published September 21 on the preprint platform bioRXiv , has not yet been peer-reviewed.

In addition to testing the hair found in the Bible, the researchers also collected genetic material from multiple confirmed samples of Jefferson’s hair, held in the collection of the Smithsonian. They compared that with DNA from descendants of multiple lineages: Jefferson and his wife Martha, Jefferson’s brother Randolph, and two of Hemings’ sons, Eston and Madison. (Hemings had four children who lived to adulthood, but only Eston and Madison claimed Jefferson as their father).

Matches in the DNA suggest the chance that Thomas Jefferson fathered at least one of Sally Hemings’ children was 99.96%.

Previously, a genetic study from 1998 led by the late Eugene Foster, a retired pathology professor at Tufts University and the University of Virginia, claimed to prove Jefferson’s parentage of Hemings’ children. That study found a rare haplotype — a combination of genes — in the Y chromosomes of males descended from Thomas Jefferson’s uncle. That same haplotype existed in descendants of Hemings, too. However, many experts questioned Foster’s claim for one very important reason, Kurin told CNN.

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“He didn’t have Thomas Jefferson’s DNA,” Kurin said. “He didn’t have something to directly compare living descendants of the Jefferson family to Madison Hemings and Eston Hemings and others that might have been the descendants of Thomas Jefferson.” Critics of that the 1998 study said Foster’s evidence merely connected Hemings’ descendants to a male in the Jefferson lineage, and not necessarily to the former president.

“I thought, if we can get Thomas Jefferson’s DNA, we could use that as the source of comparison to various descendants, and really firmly solve the question,” Kurin said.

Kurin and his team were initially disappointed to find that the Bible hair wasn’t the smoking gun that they thought it would be. To check whether the hair was Jefferson’s, they compared its DNA with that of a living woman who was a direct descendant of Thomas Jefferson’s mother along the family’s female lineage. They expected to find identical mitochondrial DNA, which is genetic material specifically inherited from the maternal side. But their hopes were dashed when the two samples didn’t match.

Still, they were able to access other hair samples that records attributed to Thomas Jefferson. These hairs, including a lock clipped at his deathbed, were in a packet provided by the Thomas Jefferson Foundation at Monticello, and had not previously been available for analysis. The scientists reconstructed and compared historic genome sequences of Jefferson and Hemings with DNA collected from 16 living individuals, including multiple descendants of Eston and Madison Hemings. These analyses found matches across genomes that linked Hemings descendants to Thomas Jefferson.

“What made this study so powerful is that researchers weren’t just comparing two genomes,” said Éadaoin Harney, a senior population geneticist at the 23andMe Research Institute. “Instead, they collected DNA samples from multiple people from different branches of the family tree.”

Ian Aktins/Thomas Jefferson Foundation at Monticello

In genetic analysis, larger sample pools provide more robust conclusions, said Harney, who was not involved in the new research. “By studying the patterns of DNA sharing across all of these individuals, it became possible to disambiguate exactly how the descendants of Sally Hemings were related to Thomas Jefferson,” she told CNN in an email.

While the new book and paper focus on genomic data of well-known historical figures, these methods are also broadly useful for illuminating the obscured history of enslaved people, which has been a focus of Harney’s own research. In a 2023 study of enslaved and free African Americans from Maryland, Harney used DNA analysis combined with other biomolecular and archaeological techniques to uncover individuals’ ancestry and places of origin. The data also suggested links to people who still live in Maryland.

“Historical records are full of gaps, particularly when it comes to documenting the lives of people who occupied less privileged places in society,” she said. “This is particularly true for enslaved Africans and African Americans, who are often only described in historical records as property.”

Genetic analyses, such as those used in the new Jefferson study, can help restore connections that were lost because of slavery, Harney added. “The same tools can be applied to study the many enslaved people whose lives were never well documented, and help reconnect them with their descendants.”

Whispers about Jefferson’s sexual relationship with Hemings — who was 30 years his junior and a half-sister to his wife — have endured for more than 200 years. Initial rumors were fueled by local innuendo and supported by records aligning Hemings’ pregnancies with Jefferson’s presence at his plantation home of Monticello in Virginia. An article published in 1902 in the Richmond Recorder stated that “there is not an individual in the neighbourhood of Charlottesville who does not believe the story,” regarding Jefferson fathering children with Hemings.

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Though the conclusions of Foster’s 1998 study were not universally accepted, that genetic evidence was compelling enough for the Thomas Jefferson Foundation to issue a statement two years later acknowledging “the strong likelihood that Thomas Jefferson and Sally Hemings had a relationship over time that led to the birth of one, and perhaps all, of the known children of Sally Hemings.”

Finally laying that uncertainty to rest was enough of a motivation to keep Kurin and the other researchers going for more than a decade, despite their initial disappointment that the hair found in the Bible did not belong to Thomas Jefferson, he said.

“We had hit a dead end, but scientists are always looking for alternatives,” he said. “I think we were propelled still by scientific and historical curiosity.”

While the question of Jefferson’s ancestry in Hemings’ descendants may finally have been answered, another remains: Whose hair was pressed in Jefferson’s bible? The researchers had collected enough of its fragmentary genetic data to know that it belonged to a female member of the Jefferson family, but that was all the information the team could learn, Kurin said.

“It’s like a partial fingerprint,” he explained. “That is still a lingering mystery.”

Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American and How It Works magazine. She is the author of “ Rise of the Zombie Bugs : The Surprising Science of Parasitic Mind-Control” (Hopkins Press).

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2011年，史密森尼美国国家历史博物馆的工作人员打开一本曾属于托马斯·杰斐逊的圣经时，在书页间发现了一根红金色的头发。这根头发被怀疑属于杰斐逊本人，由此展开了一项历时十余年的DNA调查。如今，这项调查为揭开杰斐逊与他家中的奴隶萨莉·海明斯之间关系的谜团提供了一块缺失已久的拼图。

经过数年对DNA片段的重建，科学家们揭示了迄今为止最有力的证据，表明美国开国元勋之一的杰斐逊也与萨莉·海明斯育有子女——这段关系长期以来一直有传闻，但从未得到确凿证实。这项调查的进展过程记录在理查德·库林（Richard Kurin）所著的《一线之隔的历史：托马斯·杰斐逊、萨莉·海明斯与解开一个两百年的谜团》（History by a Hair: Thomas Jefferson, Sally Hemings & Solving a 200-Year-Old Mystery）一书中，该书于9月22日出版。库林是一位杰出的学者，也是史密森学会的特派大使。

库林也是一篇论文的资深作者，该论文描述了将美国前总统与海明斯的后裔联系起来的方法，其中涉及对杰斐逊和海明斯家族谱系进行深入的遗传学研究。该论文于9月21日发表在预印本平台bioRXiv上，尚未经过同行评审。

除了对《圣经》中发现的头发进行检测外，研究人员还从史密森学会收藏的多份经鉴定的杰斐逊头发样本中提取了遗传物质。他们将这些遗传物质与来自多个血统的后裔的DNA进行了比对，这些后裔包括：杰斐逊及其妻子玛莎、杰斐逊的兄弟兰道夫，以及海明斯的两个儿子埃斯顿和麦迪逊。（海明斯有四个孩子长大成人，但只有埃斯顿和麦迪逊声称杰斐逊是他们的父亲。）

DNA 比对结果表明，托马斯·杰斐逊至少是萨莉·海明斯其中一个孩子的父亲的概率为 99.96%。

此前，已故的尤金·福斯特（Eugene Foster）——塔夫茨大学和弗吉尼亚大学的退休病理学教授——领导的一项1998年的基因研究声称，该研究证明了杰斐逊是海明斯孩子的亲生父亲。这项研究在托马斯·杰斐逊叔叔的后代男性的Y染色体中发现了一种罕见的单倍型——一种基因组合。海明斯的后代也存在同样的单倍型。然而，库林告诉CNN，许多专家对福斯特的说法提出了质疑，原因非常重要。

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研究人员称他们已验证并测序了希特勒的DNA。他们的发现是一个引发争议的重磅炸弹。

库林说：“他没有托马斯·杰斐逊的DNA。他没有办法将杰斐逊家族的在世后裔与麦迪逊·海明斯、埃斯顿·海明斯以及其他可能是托马斯·杰斐逊后裔的人进行直接比对。” 1998年那项研究的批评者认为，福斯特的证据仅仅将海明斯的后裔与杰斐逊家族的一位男性联系起来，而未必能直接与这位前总统联系起来。

库林说：“我当时想，如果我们能获得托马斯·杰斐逊的DNA，我们就可以将其作为与各种后裔进行比较的来源，从而真正彻底地解决这个问题。”

库林和他的团队最初很失望地发现，圣经中发现的头发并非他们预想中的关键证据。为了确认这根头发是否属于杰斐逊，他们将头发的DNA与一位在世女性的DNA进行了比对。这位女性是托马斯·杰斐逊母亲的直系后裔，属于家族的母系血统。他们原本期望找到完全相同的线粒体DNA，因为线粒体DNA是专门从母系遗传的遗传物质。然而，当两个样本的DNA不匹配时，他们的希望破灭了。

尽管如此，他们还是获得了其他一些据记载属于托马斯·杰斐逊的头发样本。这些头发，包括一缕在他临终前剪下的头发，装在一个由蒙蒂塞洛的托马斯·杰斐逊基金会提供的包裹里，此前从未进行过分析。科学家们重建了杰斐逊和海明斯的历史基因组序列，并将其与从16位在世个体（包括埃斯顿和麦迪逊·海明斯的多个后裔）身上采集的DNA进行了比对。这些分析在基因组中发现了匹配项，将海明斯的后裔与托马斯·杰斐逊联系起来。

“这项研究之所以如此有力，是因为研究人员不仅仅是在比较两个基因组，”23andMe研究所的高级人口遗传学家埃达奥因·哈尼说。“相反，他们收集了来自家族树不同分支的多人的DNA样本。”

伊恩·阿克廷斯/托马斯·杰斐逊基金会（蒙蒂塞洛）

哈尼表示，在基因分析中，更大的样本量能够得出更可靠的结论。她并未参与这项新研究。她在给CNN的电子邮件中写道：“通过研究所有这些个体之间的DNA共享模式，我们就能准确地弄清楚萨莉·海明斯的后代与托马斯·杰斐逊之间的关系。”

虽然这本新书和论文主要关注知名历史人物的基因组数据，但这些方法也广泛适用于揭示奴隶制时期鲜为人知的历史，而这正是哈尼本人研究的重点。在2023年一项针对马里兰州被奴役和自由的非裔美国人的研究中，哈尼结合DNA分析和其他生物分子及考古技术，揭示了个人的祖先和出生地。数据还表明，他们与一些至今仍居住在马里兰州的人存在联系。

“历史记录存在诸多空白，尤其是在记录社会地位较低人群的生活方面，”她说道。“对于被奴役的非洲人和非裔美国人来说尤其如此，他们在历史记录中往往只被描述为财产。”

哈尼补充说，像杰斐逊大学这项新研究中使用的基因分析方法，可以帮助恢复因奴隶制而中断的血缘关系。“同样的工具也可以用来研究许多生平事迹从未被详细记录的奴隶，并帮助他们与后代重新建立联系。”

关于杰斐逊与海明斯（比他小30岁，是他妻子的同母异父妹妹）的性关系的传闻已经流传了200多年。最初的谣言源于当地的暗示，并得到了记录的支持，这些记录显示海明斯怀孕期间，杰斐逊曾到访他在弗吉尼亚州蒙蒂塞洛的庄园。1902年，《里士满记录报》发表的一篇文章称，“夏洛茨维尔附近没有人不相信”杰斐逊与海明斯育有子女的故事。

图片在线/环球图片集团/盖蒂图片社

通过19世纪无名墓穴中的DNA揭示乔治·华盛顿家族的秘密

尽管福斯特 1998 年的研究结论并未被普遍接受，但该遗传证据足以让托马斯·杰斐逊基金会在两年后发表声明，承认“托马斯·杰斐逊和萨莉·海明斯很可能随着时间的推移发展出某种关系，并最终导致了萨莉·海明斯已知子女中的一个，甚至可能是所有子女的出生”。

库林说，尽管最初得知在《圣经》中发现的头发并非托马斯·杰斐逊的遗骸时感到失望，但最终消除这种不确定性足以激励他和其他研究人员坚持研究十多年。

“我们一度陷入了僵局，但科学家们总是在寻找其他出路，”他说。“我认为，科学和历史的好奇心仍然是我们前进的动力。”

虽然杰斐逊的祖先是否在海明斯的后代中有所体现这个问题或许终于得到了解答，但另一个问题依然存在：杰斐逊圣经里压着的那根头发究竟是谁的？库林说，研究人员收集到的零碎基因数据足以让他们确定这根头发属于杰斐逊家族的一位女性成员，但这已经是研究团队所能了解到的全部信息了。

“这就像部分指纹一样，”他解释说。“这仍然是一个悬而未决的谜团。”

明迪·韦斯伯格是一位科学作家和媒体制作人，她的作品曾发表在《Live Science》、《Scientific American》和《How It Works》杂志上。她是《僵尸虫的崛起：寄生虫精神控制的惊人科学》（霍普金斯出版社）一书的作者。