
This illustrates that the media and elites have been using this ploy for a long time. I am talking about the Afghan girl photograph, or the foregrounding of blonde and blue-eyed Yezidi children. Recently I expressed some irritation on Twitter when there was a prominent photograph of a hazel-eyed Rohingya child refugee being passed around. Something like 1 in 500 people in that region of the world has hazel eyes! That couldn’t be a coincidence. Race matters when it comes to compassion.

According to 23andMe’s database about 1 out of 10 white Southerners has African ancestry at the 1% threshold. It would be even more if you dropped to closer to 0.5%. And the DNA ancestry here understates the extent of what was going on: at about 10 generations back you are about 50% likely to inherit zero blocks of genomic ancestry from a given ancestor (assuming no inbreeding in the pedigree obviously). And this is exactly when a lot of the ancestry that is being detected seems to have “entered” the white population. In other words, for every person who is 1% African and 99% white American, they have a sibling who is 0% African and 100% white American, even though genealogically they share the same ancestors. Dropping the threshold to closer to 0.3%, and considering that even in the South there was migration from the North, and to a lesser extent Europe, after the Civil War, I wouldn’t be surprised if models of admixture inferred from the distributions we see indicate that over half the lowland Southern white population likely had genealogical descent from a black slave.

The reason is obvious in the context of American history. Thomas Jefferson’s slave Sally Hemings had three white grandparents and one African slave grandparent. Several of her children are recorded to have been totally European in an appearance, and all except one passed into the white population (the two eldest married well into affluent white families in Washington D.C.). Passing as white was a way to escape the debilities of black status in the United States.


But the attitudes toward racial segregation and mixing took decades to harden. Martin van Buren’s vice president, Richard Mentor Johnson, was well known to have had a common-law wife, Julia Chinn, who was a slave. He recognized his two daughters by her. He was vice president from 1837-1841 in the more racist of the two American political parties of the time. It is hard to imagine this being a viable “lifestyle” choice for someone of this prominence in later decades (after Julia Chinn’s death Johnson continued to enter into relationships with slaves).

Which brings us back to what was happening in the decades around 1800. Racism was a fact of life, necessitating the need for passing. But, beliefs about racial purity and the one drop rule had not hardened, so it would not be surprising to me that it was much easier for slaves or ex-slaves with mostly European ancestry to change their identity. Perhaps white Americans of that period were simply less vigilant about someone’s background because they were genuinely less concerned about the possibility that their partner may have had some black ancestry, so long as they looked white.
As the databases grow larger we’ll get a better sense of the demographic and genealogical dynamics. My suspicion is that we’ll see that there wasn’t much diminishment of gene flow into the black-identified community over the past 200 years, as much as the fact that hypo-descent, the one-drop rule, became so powerful in the between 1850 and 1950 we can confirm that passing declined, before rising again in the 1960s as whites became less vigilant due to decreased racism.
* As a middle class New Englander John Adams obviously was no aristocrat, but he was no populist either.


A second cousin had her autosomal DNA tested by 23andMe and turned up with <1% of Sub-Saharan African ancestry. It's a single tiny stretch on one chromosome. Possibly a lab error. The simple-minded calculation says 10 or more generations.
She wasn't bothered by it, but a couple of generations ago people in my family would have been one-droppers. A recent article in NYT had interviews with people who had the test and some were disappointed that they didn't nave Native American ancestry which was expected from family lore. In colonial Virginia, it wasn't a matter of pride. Except for Pocahontas.
John Wayles was a descendant of Katherine Banks Isham, mother-in-law of William Randolph, which makes me a relative of Jefferson, his wife and Sally. There are portraits on the internet of Sally and her mother Betty, and they look white.
Sociology is beyond my job description, but something happened to harden opinions in the early 19th Century. A lawyer who married into the Randolph family was the legal faculty at William and Mary. Around 1790 he wrote a treatise on the law of slavery. He concluded that the supposed legal protections against mistreatment were totally ineffective and proposed phasing it out by having the stat reimburse the owners. There were no negative consequences. He went on to a Federal judgeship. If he'd made that suggestion in 1850 in New Orlealns, they'd have strung him up.
A second cousin had her autosomal DNA tested by 23andMe and turned up with <1% of Sub-Saharan African ancestry. It's a single tiny stretch on one chromosome. Possibly a lab error. The simple-minded calculation says 10 or more generations.
it’s not lab error. lab errors are going to be really obvious. it may be artifactual error (something to do with the statistical inference). if it’s 0.5% or above i doubt it’s artifactual error
I am super pale, blonde, and from a very “Wonderbread White” family. Most of my ancestors had been in the USA even before The Revolution. Imagine my surprise when my 23 and me said I was just shy of 3% African.
I believe the source of my Sub-Saharan DNA was my paternal Grandmother’s Grandfather. He lived in Kentucky and had long, straight, black hair and was a bit tan. He told everyone that he was from an Indian Tribe. I have 0 Native American ancestry, so we guess that he was a light skinned Black man. I figure he was just trying to make it back in those days, and that was his cover story!
So maybe all those 1/64 “Cherokee” White people are really 1/64 Black African 😉
hm. if i do math right, he should have been ~50% african. hard to imagine he could have passed unless he was from a mixed background on BOTH sides and somehow got a more white phenotype. happens. course he could be less and you got ‘more’ of him.
Sorry, it was 0.1%, not 1%. So perhaps only one SNP. I was thinking a simple mechanical glitch or noise in the procedure.
I could get the same test, but there’s only a 1/8 chance I got the segment even if it comes from a common ancestor. She has 3 siblings, which could be more informative.
.1 could be artifactual. 23andMe knows i’m sure, probably tested n. european out-samples….
My roots in this country go back to the early 18th century, and they are in Pennsylvania or West Virginia (that is, the non-slaveholding part of Virginia). I’d be very surprised if my ancestry has any African roots, but keep meaning to nag the folks who took my DNA and promised me an analysis.
But if I show up with any non-trivial amount African, it’d mean there was more interracial mixing than generally assumed, because Jefferson County and West Virginia are extremely white places.
one thing to remember is that after 1800 there was migration north from south and vice versa. though a lot of that (‘south’ to north were scots-irish into what became butternut territory).
I have tested 1st cousins at 23andMe and among the 5 of us we show European, Finnish, Iberian, Middle Eastern and North African, Sub-Saharan African, and East Asian and Native American. They are all related to me through both of my parents. Yes, old line US colonials.
I recently did a blog post on slaves owned by my ancestors and relatives. Approximately 120 people. The wills and deeds describe Blacks or “Negroes”, an Indian, and white people who were sold with land or given to family members. See,
https://scpgen.blogspot.com/2017/08/slave-name-roll-project.html