Yesterday I wrote about Prof. Annette Gordon-Reed reexamining the evidence about the paternity of Sally Hemings’s children in 1997 and concluding that certainty lay in the realm of medical science, not documentary history.
That’s where Eugene A. Foster, M.D., entered the picture. He had been a pathologist and professor of forensic medicine at Tufts and the University of Virginia. Like Gordon-Reed, he was trained to think rigorously about evidence. Foster had read about the question of whether Hemings’s owner, Thomas Jefferson, fathered those Hemings children, and wondered if there could be a genetic answer.
These remarks come from Frontline’s interview with Foster:
The experts and I had thought that, after five, six or seven generations, the DNA of the person who you’re interested in...would be diluted so much that you can hardly find any. In other words, in each generation, a parent passes on only half or less of his or her DNA to the children, so with each generation, it begins to disappear. So even if we knew what was specifically characteristic of Thomas Jefferson’s DNA, we would have very little chance of finding it in people who are his descendants or think they’re his descendants.Foster’s contribution to history was to apply a new discovery in medical science to an old, seemingly intractable question. He turned what seemed like a boring quality in genetics—“not enough variation” in men’s Y chromosome—into an advantage when it came to studying paternity nearly two centuries before.
And then the whole thing was complicated because of other family relationships, like the fact that Sally Hemings and Thomas Jefferson’s wife probably had the same father. The Carr brothers, who were also implicated in this affair, had ancestors common with the Jeffersons, and so forth. So it was just going to be impossible. . . .
But the Y chromosome is something that is passed. It’s the chromosome that determines whether you are a man. So a man has the Y chromosome and an X chromosome and the woman has two X chromosomes. The beauty of that is, since you only have one Y chromosome and it’s gotten only from your father, that means it isn’t diluted. It goes from generation to generation, father to son, unchanged. No one had thought of using it for these purposes, because it had not been thought to have enough variation.
With the assistance of genealogist Herbert Barger and others, Foster located patrilineal (i.e., son of a son of a son...) descendants of Thomas Jefferson’s paternal uncle, one Hemings child, Thomas Woodson, and the Carr brothers. Then a team of British and Dutch geneticists tested those men’s Y chromosomes to find close matches, and some British statisticians analyzed the results.
Foster published the team’s findings in Nature in 1998, and the news immediately made headlines. They had found a match between the Jefferson and Hemings lines, and no match between those lines and those of the Woodson or Carr families. Given the elimination of any Carr link to Sally Hemings’s children, the documentary evidence already pointing to Thomas Jefferson as their father, and the total lack of evidence from the nineteenth century pointing to any other Jefferson, Foster’s study settled the question for most historians and other observers.
What I find especially convincing about this analysis is that no one in the nineteenth century could have predicted D.N.A. science, or known who would have patrilineal descendants alive in 1998. In other words, someone making up a story about the Hemings children in the 1800s had no idea what evidence that story would have to match and explain in the future. And of all the detailed accounts of the Hemings family set down in the nineteenth century, only one—the memories of Madison Hemings—was fully consistent with the Foster study.
Foster died last week at age 81, and his obituaries led with his Jefferson work.
TOMORROW: The mystery of Thomas Woodson.