Analysis of a white reader’s DNA reveals results that may warrant scientific study.
Dear Professor Gates:
According to the 23andMe DNA-testing service, I have 0.1 percent West African DNA from my mother. I also have approximately 5-6 percent Native American from my mother, who is now deceased.
I have a studio portrait of my great-grandmother Luisa Gomez taken on the Plaza in Santa Fe, N.M., about 1881-1883, and she looks (about 16 to 20 years old) to have Native American and European blood, though I know looks can be deceiving.
I have paper-traced my maternal great-great-grandmother, Carlota Gomez, and third great-grandmother Trinidad Gomez to Santa Fe. In the U.S. census records for 1850 and 1860, both women report being born in Mexico.
My mitochondrial DNA result is L1c2b1, according to the report I received, which further said, “Haplogroup L1c has been largely restricted to central Africa since originating in its equatorial forests about 60,000 years ago. It is extremely common among western pygmy populations such as the Biaka and Bakola, where it appears to be universal. It is also found among African-Americans.”
So my question is, with the addition of the African haplogroup test result, does that make the 0.1 West African DNA more likely to be real? If so, with the addition of Native American ancestry, could my great-grandmothers have had an Afro-mestizo maternal ancestor? —Ellen
That’s an interesting question, with an even more interesting answer. I consulted with genetic genealogist CeCe Moore about your DNA results and have included her response below. As you will see, your hunch that the mitochondrial DNA result bolsters the likelihood that you have sub-Saharan African ancestry was a good one.
Because Moore further indicated that your DNA may be unique enough to warrant scientific study, I have opted to present her response as received, without editing out any technical terminology in favor of laymen’s terms that may be less precise.
For those following along, a short primer on the terminology:
Autosomal DNA is the type of DNA we inherit from all of our ancestral lines, but not from all of our ancestors after about six generations.
Mitochondrial DNA (mtDNA) is inherited from direct maternal ancestors.
A haplogroup is a genetic population group of people sharing a common ancestor on their direct maternal or paternal lines.
A subclade, in this context, is a subgroup of a haplogroup.
Mthap refers to mtDNA haplogroup analysis.
With all that being said, here is CeCe Moore’s reply:
First, let me say that I find Ellen’s DNA results very compelling! The combination of her admixture and maternal haplogroup reveals a fascinating history.
A Deeper Look Into Ellen’s Autosomal DNA Results
We would expect Ellen to inherit approximately 6.25 percent of her autosomal DNA from her second great-grandmother Carlota. Since we inherit autosomal DNA from all of our ancestors going back about six generations, this means that Carlota likely did not have a substantial amount of African admixture, since Ellen’s results include only 0.1 percent African.
However, of significance is the fact that 6 percent of Ellen’s DNA was predicted to be of Native American and East Asian origin, and that would be consistent with inheritance from a second great-grandparent of full Native American ancestry.
To address the question of whether the small DNA segment of predicted West African origin is real, I adjusted the confidence-level tool included with 23andMe’s Ancestry Composition admixture feature. In this case, that prediction was highly confident, and the West African percentage remained even as I adjusted the tool to 23andMe’s highest confidence level of 90 percent. I also noticed while analyzing the Chromosome View that Ellen’s DNA segment of predicted African origin was immediately adjacent to a larger segment of predicted Native American origin of high confidence. This pattern of inheritance seen on Ellen’s 15th chromosome suggests that the African ancestry was likely inherited from the same ancestor as the Native American DNA.
We also see a significant amount of Iberian ancestry in her results. The combination of Iberian and Native American is common among those of Latin American ancestry, although we typically see a higher amount of African ancestry in conjunction with the other two in these population groups.Loading...
Ellen’s case also reinforces the fact that testing a parent can significantly increase our ability to draw genealogical conclusions based on our DNA results. Since she has tested her father, this has confirmed that the Native American and West African DNA come from her mother’s side of her family, as theorized. (23andMe offers a feature called “Split View” that subtracts out the tested parent’s contribution to the admixture from that of the child. Testing a parent also allows 23andMe to assign the maternal contribution to the top chromosome of the pair in the Chromosome View.)
Findings That Raise Interesting Questions
Also notable in the chart is the large block of unassigned DNA near the middle of Ellen’s maternal chromosome 9. This means that there is no match to that portion of her DNA in 23andMe’s large collection of reference samples, and that indicates to me that there is something of interest yet to be discovered in her DNA. This segment is directly adjacent to a block of predicted Native American DNA, and there are many other smaller unassigned sections in the middle and at the ends of some of Ellen’s other Native American segments. From this I would theorize that perhaps Ellen descends from a Native American population whose members’ DNA has not yet been largely sampled.
Now let’s look at Ellen’s mitochondrial DNA haplogroup subclade. It is extremely interesting and unique. This branch of the mitochondrial DNA (mtDNA) tree of mankind is of relatively recent African origin. To analyze Ellen’s mtDNA, I used two sites built by citizen-scientist genetic genealogists. First, running her raw data file through James Lick’s mthap third-party tool predicts that her subclade is actually L1c2b1a1 (with some “extra” markers that may be private mutations).
Then I turned to Rebekah Canada’s brand-new Encyclopedia of mtDNA Origins in order to learn more about the origins of this subclade. There is not much data on this subclade to date, but the Encyclopedia of mtDNA Origins tells us, “From Geno 2.0 data, samples with known maternal origins come from the British Territories, the United States, and Mexico.” Further, we also learn from Canada’s site that this subclade’sparent branches have descendants found in the Caribbean and connections to both the West Central African Pygmy population and the Luhya from Webuye, Kenya.
Following the geographic origins specific to this mtDNA subclade and those of its parent branches back through time may be informative of the migration route of Ellen’s direct maternal ancestors: enslaved from Africa, brought to the Caribbean and eventually taken to the Americas. The fact that there is little data and that Ellen’s mutations are not an exact match to any others I found indicates to me that her DNA may be important for scientific research. I strongly suggest that she test her full mitochondrial DNA (offered only by Family Tree DNA) and donate her sequence toGenBank so that scientists will have access to it for research purposes. This is how we as a community can help science to progress and, in turn, learn more about our individual and collective histories.
In conclusion, the DNA leaves no doubt that Ellen has African ancestry inherited from her matrilineal second great-grandmother, Carlota, and her mother, Trinidad Gomez, and that they had African ancestry on their direct maternal ancestral line. Ellen’s admixture reveals that this ancestral line mixed with the Native and European populations in Mexico, and perhaps also the Caribbean, going back many generations. This is a wonderful example of how our DNA can tell us stories about our ancestors that the written records often cannot.
Henry Louis Gates Jr. is the Alphonse Fletcher University Professor and founding director of the Hutchins Center for African and African American Research at Harvard University. He is also chairman of The Root. Follow him on Twitter and Facebook.