The Updated Ancestry DNA Results Are In!

Between 1525 to 1800, multiple ancestors of mine were enslaved in West Africa, survived the Middle Passage, endured lives of toil in Colombia, and maybe even escaped to freedom on the Colombian frontier of settlement, living in tiny rochelas or larger palenques. One of the few ways I may ever learn anything about my African ancestors is through exploring my genetic admixture.

AncestryDNA has updated its formulas for adxmiture, giving me a new "ethnicity estimate" that compares my DNA to people from over 1,000 regions. The resulting map, seen above, is very satisfying. I seem to embody the cliche three regions of Latin American origin -- Africa, the Americas, and Europe.

My results in these three regions have been consolidated. Ancestry assigned me to two broad Native American subregions, "North, Central, and South American" and "Andean," and now I am more specifically assigned to "Indigenous - Colombia and Venezuela" and "Indigenous Eastern South America." The latter category makes sense to me, since Caribbean people like the Arawak have Amazonian origin.

Within Europe, AncestryDNA first saw traces of Italy but now finds Basque genetic markers. My Ashenazi Jewish and Western European markers (Spain, France, Belgium, and the United Kingdom) appear in both tests.

Asia, represented in my first AncestryDNA test by traces of Middle Eastern genetic markers, is now missing.

And what about Africa? My first AncestryDNA test found links with "Benin and Togo" and "Cameroon, Congo, and southern Bantu populations." Now, my revised AncestryDNA results find matches only with Nigeria, the region between the first two areas.

It's hard not to read into these results and draw interpretations about my genealogy, but it is risky to do just that. Genealogist Roberta Estes explains it very well -- these admixture tests are not scientific, and are only reliable for finding which continents our ancestors came from. Once we try to pick apart subregions of a continent, the genetic similarities of neighboring populations makes it almost impossible.

The blog Tracing African Roots has an interesting series called "Did Ancestry Kill Their African Breakdown?" that shows AncestryDNA's mixed record at identifying African populations. Among the groups that seemed overrepresented in Ancestry results were "Benin and Togo" and "Cameroon, Congo, and southern Bantu populations," which both showed up in my first test. I'm curious to see how Tracing African Roots evaluates the updated AncestryDNA results.

Admixture percentages are up in the air, but there is a more scientific way to visualize admixture: the PCA plot! Your personal genetic blend appears as a dot amid a particular set of populations, showing in a visual way your relationship to the various groups. The populations you pick will influence the appearance of the final chart. I'm able to use my Eurogenes K15 results on GEDmatch to build my own PCA plot, seen in part below:

I am the lonely purple dot on this PCA plot. This chart has its own limitations, since it shows the summary of my genetics, with no list of contributing elements. I am closest to the Ashkenazi Jewish population, a group that contibuted roughly more than half of my ancestry. My dot drifts a little north of the Ashkenazi dot, towards the direction of the Western European and Native American populations. There is no way to infer percentages, subregions, or the other tantalizing fictions of the "ethnicity estimates."

Geneticist Razib Khan of Insitome is a great advocate of the PCA plot. Comparing populations this way, he says "You recognize patterns which were otherwise unrecognizable. But how you interpret those patterns, that’s a wholly different matter. And how those patterns arise is also not something one can ignore." He gives further explanations of PCA plots, using his own genome and his daughter's genome as examples.

Questions? Comments? Write me at ruedafingerhut (at) gmail (dot) com.