Final summary: Central & Southern African AncestryDNA results 2013-2018

Without wanting to rehash things this blog post and following ones will provide a quick recap of my final AncestryDNA survey findings for continental Africans. These results were obtained during 2013-2018 but I had not fully processed all the data up till now. Starting with my Central & Southern African section. Which I first published on 17 February 2017 when I had only 32 Central & Southern African AncestryDNA results available for my analysis (see this overview). As my survey has been ongoing I have managed to collect a sample group which is now three times greater. Consisting of no less than 96 AncestryDNA results of Central & Southern African persons! Follow the link below for detailed analysis & new screenshots:

Table 1 (click to enlarge)

stats (n=92)

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I discontinued this survey after Ancestry’s update in September 2018. Because in my opinion Ancestry’s new version of their ethnicity estimates regrettably has been a downgrade in regards to their African breakdown, overall speaking (see also this blogseries). Which is why I think these “old” results may still be useful and are not obsolete yet. I originally singled out two main implications for Afro-Diasporans or rather propositions which I will briefly revisit in this blog post. Also in order to tie up some loose ends.

  1. Congolese & Angolan ancestry more likely than Cameroonian ancestry?
  2. Southwestern Bantu ancestry much more likely than Southeastern Bantu ancestry?

Then again my intention is not only to look backwards but also forwards! In particular I believe that this dataset may provide a helpful baseline to compare with 23andme’s newly updated African breakdown (see this overview). As well as functioning as a benchmark for Ancestry’s upcoming update, which hopefully this time will lead to improvement!

Over all I would say that my African survey findings are pretty much reinforcing the main message I have been trying to get across from day 1: the labeling of ancestral categories in DNA testing is often not be taken too literally. However this does not mean you cannot derive a great deal of informational value from your socalled ethnicity estimates! Proper interpretation is a precondition. And it has been my experience that being aware of the DNA results of native Africans certainly helps in this regard. Even more so when also taking into account your African DNA matches, relevant historical context, (advanced) genetic genealogy and other means of follow-up research.

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compil CSA3

A selection of some of the new results I have added into my survey. Extending the country range. And finally now also able to showcase Angolan breakdowns. Take notice that one of them has “Cameroon/Congo” as primary region while the other shows so-called “Southeastern Bantu” in first place!

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23andme’s new African breakdown put to the test

My first DNA test ever was with 23andme. Nine years ago already! In January 2010 I was thrilled but soon afterwards also quite underwhelmed to receive my very basic admixture results. The only distinction being made back then was between African, Asian and European DNA. Native American DNA did not even have a separate category yet 🙂 As I am of Cape Verdean descent I was actually most anxious to have my Upper Guinean lineage confirmed. Instead my African score just pointed towards the entire continent! One of my immediate reactions at that time therefore was:

“I hope that one day 23andme’s Ancestry Reports will be helpful in finding out where to locate my ancestry regionally and not just on a continental scale.”

After a (very) long wait it seems that this day has finally arrived! Last month 23andme rolled out an updated version (3.0) of Ancestry Composition to all their customers. Regardless of when they originally took the test. This update has actually been on release since September 2018 for 23andme’s most recent customers. But to its credit 23andme also made this update available to its earliest customers, like myself. Over the years I have been through more than one update on 23andme already. But this is the first time I can say that finally a meaningful African breakdown is being provided! For more details see:

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Figure 1 (click to enlarge)

23andmecompil

Updated 23andme results from across the African continent. A small but representative sample. Highlighting how 23andme’s new African regions appear to be quite predictive, for native Africans themselves. Unrealistic expectations about “100% accuracy” as well as counter-productive obsessing about regional labeling should be avoided. Instead take note of how the expected regions (circled in red by myself) reach levels of over 70% reaching into 98%! Taking a macro-regional perspective (combining overlapping regions from within West Africa versus Central/Southern Africa versus Northeast Africa) these results are usually in line as well. Also the additional ancestral locations appearing below the regional scores are on point!

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I have always believed that the best way to find out about the predictive accuracy of any particular DNA test or update is to look at the results of people who actually know their (recent) origins. In order to improve correct interpretation I have therefore started a survey among African DNA testers (n=173). Using their group averages as some sort of rudimentary benchmarks so to speak. Similar to the survey I conducted among African AncestryDNA testers in previous years (see this page). Of course also some basic knowledge about DNA testing (in particular 23andme’s reference populations and methodology) as well as historical context will remain essential to really get the most out of your admixture results!1

Main topics if you continue reading:

  1. Survey findings for 173 African 23andme testers from 31 countries (incl. 25 Cape Verdeans)
  2. Maps showing the geographical distribution of the new African regions on 23andme (based on my survey findings)
  3. Implications for Afro-Diasporans
  4. Examples to illustrate how regional admixture DOES matter!

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DNA matches reported by 23andme for 75 Africans

Wishing to share the vibranium 😉 I have created a new page featuring the DNA matches reported by 23andme for 75 Africansall across the continent. These results were collected by me in 2015 when 23andme’s Countries of Ancestry (CoA) tool was still available.

My survey results might have limitations in several regards but I do believe these African CoA results can still reveal relevant tendencies in DNA matching. I intend to compare these preliminary matching patterns eventually with my more recent findings for Africans who tested on Ancestry. I provide detailed background info as well as screenshots of the individual results on this page:

(click to enlarge)

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