Geneticists are people of their time. I’m rather sure that if Charles Davenport had written a book with the title Race Crossing in Jamaica today it would end with a far different moral, because the dominant Zeitgeist in regards to racial admixture in the United States is far different nearly 100 years on. In my post below where I review interesting aspects of the new study from researchers in David Reich’s lab and 23andMe, The Genetic Ancestry of African Americans, Latinos, and European Americans across the United States, I didn’t cover the variation in admixture in black and white Americans too much in detail. Partly that’s because this study only improved the bigger picture on the margins, and with finer geographic grain (though these were interesting obviously). We knew that the vast majority of white Americans who are not Hispanic do not have detectable non-European ancestry. It has also long been reported and verified that a substantial minority of the total ancestry of black Americans is of European origin, with a small Native American fraction as well. Additionally, this non-African ancestry in black Americans varies by geography as well as individual to individual a great deal.
So I have to take issue when The New York Times posts articles with headlines such as White? Black? A Murky Distinction Grows Still Murkier. What genetics is showing is that in fact white Americans are shockingly European to an incredibly high degree for a population with roots on this continent for 400 years. If we removed all the history that we take for granted we’d be amazed that the indigenous peoples had so little demographic impact, and, that the larger numbers of people of partial African ancestry did not move into the general “white” population. This is in fact the case across much of Latin America, where many self-identified whites, blanco, have African and indigenous ancestry. But we do know the reasons for why North America was unique, a combination of a smaller indigenous population which underwent a mass die off, and folk migrations on a huge scale previously unimaginable in human history. Whole villages in Poland and Norway, not just working age males, decamped for the New World. The original Anglo settler stock on the North American seaboard underwent a period of incredible demography expansion driven by high birthrates, in particular in New England, which in the 17th century had some of the highest total fertility rates recorded in human history.
The peculiar nature of white Americans is evident in the figure to the left. You see that black Americans span the gamut from being mostly African to mostly European (I believe that individuals who are 100% European but state they are black are probably due to error in self-identification on the survey). Though it isn’t quite clear on these sorts of plots (yes, I know why there’s moderate opacity), the black American distribution of African/European ancestry is not symmetrical, but is skewed, so that a small minority of black Americans are more than 50% European in ancestry, while the majority are less than 25% European. With the Latino populations you see admixture with both Africans and Native Americans. Though typical Mexican people are presumed to be mixed between European and Native, most Mexicans seem to have low, but detectable, levels of African ancestry. This is almost certainly due to the attested slave population across the Spanish colonies. And, this is contrast to the situation in the United States, where even “Old Stock” Anglo-Americans whose ancestors have been coexistent with people of African origin for at least 250 years by and large.
My own hunch is that the contrast between Anglo-America and Latin America when it comes to admixture has a lot to do with the fact that a far larger proportion of the European settlers were female. This allowed for a total replication of European populations, norms, and mores, rather than enforcing a sort of synthesis, as was necessary in Latin America. In the Spanish colonies European males were initially very polygynous, establishing liaisons with many women, both indigenous and black. A modest stream of men from Europe could quickly “whiten” what had initially been a mixed first generation, resulting in a elite creole caste which was predominantly European, but whose Europeanization had been male mediated atop a foundational base which featured non-European women. This can explain with the mtDNA lineages are so much more indigenous than total genome content might lead one to suspect. In Latin America individuals with obvious non-European ancestry, such as Vincente Guerrero, could rise to positions of prominence, and forward the project of a European-dominated society. In contrast someone with mixed blood in the United States would have been socially marginalized, and had minimal prospects outside of a few exceptional cases (e.g., among the mixed race Creoles of Louisiana).
Of course even with balanced sex ratios relations across racial lines occurred. This brings us to the next step of a peculiarity in the ideology of white American racial supremacy: hypodescent. This is the rule by which mixed offspring inherit the racial identity and social status of the parent whose is of the inferior race. In the United States this operationally meant that children born to slave mothers of free white fathers were considered black, and condemned to slavery (this is in contrast to the official rule in Islam, where children of the master who were recognized were free). In some ways this practice seems similar to lack of rights which non-legitimate offspring experience in many societies. But in the American context it was highly racialized. The norm of hypodescent also resulted in scientific theories which buttressed it, such as Madison Grant’s contention that mixing between superior and inferior races always resulted in a population which resembled the inferior race (the law of “reversion toward the lower type”). Charles Davenport even went so far as to argue that admixture produced offspring inferior to both parental types, a form of hybrid breakdown.
It is entirely reasonable to argue that racial categories in the United States are blurred if one holds to a Platonic and essentialist view which resembles that which underpinned white racial supremacy and the law of hypdoescent. But as it is these views have no necessary scientific basis, and a percent or two of African ancestry in someone who is ~98 percent of European ancestry does not make them non-white in any rational sense. The 12 year old paper, Categorization of humans in biomedical research: genes, race and disease, has aged well in my opinion. A conclusion that 10 percent of whites in South Carolina are actually black because they have detectable African ancestry strikes me as crazy. But then, hypodescent also strikes me as somewhat crazy, though the rationale which drove it is also eminently understandable (i.e., the exclusion of illegitimate children and maintenance of a racial order). I hold that the racial lines are “blurred” only if you hold to the criteria which arose in the 17th and 18th centuries in the culture of the American South.
I will speculate. The 28 percent proportion is about where African ancestry becomes salient, or not. In a de facto sense today the law of hypodescent applies only those who have visible African ancestry. In the United States these individuals are classified as black, no matter the preponderance of their lineage. A good example here is Rashida Jones, the daughter of Quincy Jones and Peggy Lipton. Quincy Jones has had some genetic analysis done, and he is about 2/3 African and 1/3 European. The expected value then for Rashida Jones is that she is 1/3 African in ancestry, though that may vary up or down a bit (her mother is an Ashkenazi Jew). Rashida Jones regularly plays white characters in film and television, and she does so because African features are not very evident in her. In contrast, her sister Kidada is just a bit more African in her features, and profiles of them growing up have indicated that while Rashida identified with her Jewish side (and still does), Kidada felt more black. In contrast, people who are 1/4th Asian, such as Keanu Reeves, are not subject to hypodescent in the United States, because Asian features are not as salient to white and black Americans, and white supremacy in the American South was generally aimed at blacks (my friend David Boxenhorn, who is Ashkenazi Jewish, finds it amusing that both my children have lighter eyes than any of his children).
But, with the rise in intermarriage and a clearly mixed-race Latino population the lines between the races will become blurred genetically more and more. A substantial number of American children today are multiracial, and that fraction looks to increase. If 23andMe did a survey of American genetics 25 years from now I’d be much more amenable to the interpretation that the media is putting on this survey. In one generation the world of the Baby Boomers, American, black and white, will be gone. With all that being said, I think it is highly likely that many people with known non-white ancestry (e.g., 1/4th Japanese, as a blonde haired and blue eyed friend of mine is) are going to identify as white. That means that to be “white” in the United States will be much more in keeping with the norm in Latin America, where a generally European appearance and preponderant ancestry are sufficient. And, it also means that race and racism will continue to be features of American life, just as they are in Latin America. Just differently.
Related: Steve says many of the same things.