Exactly How ‘Black’ Is Black America?
A whopping 35 percent of all African-American men descend from a
white male ancestor who fathered a mulatto child sometime in the slavery era, most probably from rape or coerced sexuality. In other words, if we tested the DNA of all of the black men in the NBA, for instance, just over
one-thirddescend from a white second or third great-grandfather. In my own case, he was my great-great-grandfather, and he was most probably of Irish descent, judging from our shared y-DNA haplogroup.
I find two things quite fascinating about these results. First of all, simply glancing at these statistics reveals that
virtually none of the African Americans tested by these DNA companies is inferred to be 100 percent sub-Saharan African, although each company has analyzed Africans and African immigrants who
did test 100 percent sub-Saharan in origin. Ranges, of course, vary from individual to individual.
Spencer Wells, director of National Geographic’s Genographic Project, explained to me that the African Americans they’ve tested range from 53 percent to 95 percent sub-Saharan African, 3 percent to 46 percent European and zero percent to 3 percent Native American. So there is a lot of genetic variation within our ethnic group, as is obvious to anyone even casually glancing at black people just walking down the street.
*
According to Ancestry.com, the average African American is 65 percent sub-Saharan African, 29 percent European and 2 percent Native American.
* According to 23andme.com, the average African American is 75 percent sub-Saharan African, 22 percent European and only 0.6 percent Native American.
* According to Family Tree DNA.com, the average African American is 72.95 percent sub-Saharan African, 22.83 percent European and 1.7 percent Native American.
* According to National Geographic’s Genographic Project, the average African American is 80 percent sub-Saharan African, 19 percent European and 1 percent Native American.
The most recent study is the 23andMe one. Most of these are done by private ancestry companies who take their user base and come up with these numbers.
I found an abstract of a 23andMe study in detail here, which shows how they came up with the figures.
The Genetic Ancestry of African Americans, Latinos, and European Americans across the United States
Patterns of Genetic Ancestry of Self-Reported African Americans
Genome-wide ancestry estimates of African Americans show average proportions of 73.2% African, 24.0% European, and 0.8% Native American ancestry (Table 1). We find systematic differences across states in the US in mean ancestry proportions of self-reported African Americans (
Figure 1 and
Table S2). On average, the highest levels of African ancestry are found in African Americans living in or born in the South, especially South Carolina and Georgia (
Figure 1Aand
Table S3). We find lower proportions of African ancestry in the Northeast, the Midwest, the Pacific Northwest, and California. The amount of Native American ancestry estimated for African Americans also varies across states in the US. More than 5% of African Americans are estimated to carry at least 2% Native American ancestry genome-wide (
Figures S1 and
and1D).1D). African Americans in the West and Southwest on average carry higher levels of Native American ancestry, a trend that is largely driven by individuals with less than 2% Native American ancestry (
Figure 1B). With a lower threshold of 1% Native American ancestry, we estimate that about 22% of African Americans carry some Native American ancestry (
Figure S2).
