Four ways to find your African matches on 23andme!

In my previous blogseries I featured the latest update on 23andme intended to zoom into ethno-linguistic African lineage. Although these new ethnic group matches are very promising at this point they still very much remain a work in progress. And therefore follow-up research is still needed if you want to uncover your entire African lineage! This follow-up research can consist of several aspects. However in this blogpost I will focus on African DNA matches listed among your DNA Relatives on 23andme. 

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Figure 1 (click to enlarge)

This overview is obtained from the “Nigerian” admixture report for an African American. You can find this among your other ancestry reports on 23andme. Featuring a confirmed Igbo DNA match for him on the left. Even when he did not yet receive any ethnic group match after the latest update on 23andme.

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Figure 2 (click to enlarge)

This screenshot shows a Senegalese match reported by 23andme for a Cape Verdean person (on the left). This person did not yet receive any ethnic group match after the latest update on 23andme. However this Senegalese match serves as an alternative way to corroborate and specify African regional admixture. In this case: “Senegambian & Guinean”.

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Currently the odds of getting assigned to an African ethnic group on 23andme are still rather low. Around 20% for African Americans, according to my survey (n=100, see this overview) and about 50% for Cape Verdeans (n=50, see this overview). And even if you do get lucky than usually you will only get matched to one single ethnic group or at most 2 or 3. While realistically speaking most Atlantic Afro-descendants will have many more ethnic connections from various parts of Africa. Receiving one single African ethnic group match can of course be very valuable but it will still represent only one isolated connection with Africa out of potentially dozens or even hundreds of others.¹

In order not to get side-tracked you should therefore explore alternative ways of finding your African DNA matches yourself! And afterwards you should also conduct further follow-up research. First of all to assess if the matches you found are indeed providing a valid genealogical (IBD) connection to a plausible African lineage. And if so then you can really achieve a massive breakthrough by attempting to assign this African match to a particular familyline by triangulation and/or chromosome mapping.

In the remaining part of this blog post I will discuss the following:

1. Four ways to find your African matches on 23andme
   • Search your DNA relatives by African country of birth
   • Look for African DNA relatives listed in your regional admixture reports
   • Perform advanced filtering of your “100%” African DNA relatives (only on 23+)
   • Do a manual browse through of all your DNA relatives
2. Look for shared DNA matches
3. Considerations when dealing with DNA matches
4. Poll: how many African DNA matches have you found sofar on 23andme?

New Update on 23andme: Ethnic Group Matches within Africa! (part 2)

This is the second part of my blogseries which deals with the update last month on 23andme. Introducing no less than 25 ethno-linguistic groups from Africa to get matched with! In order to learn more about the ethnic origins of some of your African ancestors. In the first part of this series I already covered the question of how accurate these ethnic group matches might be. Follow link below for more details:

• New Update on 23andme: Ethnic Group Matches within Africa! (part 1)

In this post I will be focusing on what to expect. Basing myself mostly on the survey findings for 100 African Americans and 50 Cape Verdeans. But I will also post screenshots of updated results from other parts of the Afro-Diaspora.

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Figure 1 (click to enlarge)

These are the updated results of a Cape Verdean cousin of mine. It was already very useful how 23andme is able to pinpoint recent ancestry from Cape Verde. However with these new ethnic group matches also historically plausible origins from mainland Africa are confirmed for Cape Verdeans. Although to be sure there are many other ethnic groups from across Upper Guinea which also contributed to Cape Verde’s African Roots (see this website).

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Just to quickly repeat myself. Last month 23andme released its most recent update which could very well signal the start of a truly game-changing feature for zooming into ethno-linguistic African lineage¹. Of course this new feature on 23andme, based on matching strength, is not perfectly flawless. However despite a few shortcomings I am very excited about this update on 23andme! Because based on more than 50 updated results for Africans (see this overview) I am quite impressed with the accuracy of this tool. Also the results I have seen for 50 Cape Verdeans and 100 African Americans are actually in line with historical plausibility.

This update has already been fully rolled out.² But still the odds of obtaining even only one of the 25 ethno-linguistic groups are rather low for most people. Depending also on your background. It seems for African Americans there’s only about a 20% chance. For many people 23andme is simply not able to detect a sufficient level of matching strength. Which is inevitable given the limitations of 23andme’s current African reference database. Understandably this may come as a big disappointement. However don’t despair because this update is a work in progress and upcoming updates will eventually reach more people! Glass half full mentality also for 2022 😉

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Figure 2 (click to enlarge)

Take note that the updated results on the right only feature one ethnic group match. Despite this African American woman being over 80% African and regionally speaking from atleast 4 major areas in West & Central Africa. Of course this finding in itself is already incredibly valuable. However this possibly Fula and/or Wolof lineage most likely covers less than 5% of her total ancestry. While for her primary region “Nigerian” not a single ethnic group has appeared yet. In fact, although not being detected she might still also have additional Mandinka ancestors. To be grouped under “Senegambian & Guinean”. Follow-up research is still needed if you want to uncover your entire African lineage!   

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In the remaining part of this blog post I will discuss the following:

1. Survey findings for 100 African Americans
   • “Igbo”, “Kongo & Mbundu” and “Fula & Wolof” most frequent
2. Survey findings for 50 Cape Verdeans
   • “Fula & Wolof” and “Mandinka” most frequent
3. Updated results from other parts of the Afro-Diaspora 
   • Atlantic Afro-descendants (Brazil, Dominican Republic, Jamaica, Haiti etc.)
   • Indian Oceanic Afro-descendants (Mauritius/Réunion, Seychelles, South African Coloured, UAE)
4. Considerations
   • Recap previous disclaimers
   • Some ethnic group matches appear more frequently than others
   • Each regional admixture category potentially includes ancestors from various ethnic groups

New Update on 23andme: Ethnic Group Matches within Africa! (part 1)

Earlier this month 23andme released its most recent update which could very well signal the start of a truly game-changing feature for zooming into ethno-linguistic African lineage.¹ Going beyond the broad regional admixture categories such as “Nigerian” and “Senegambian & Guinean”. Which are already quite useful in fact. However by now providing much more granularity 23andme is really stepping up its game! For more details read this announcement by 23andme:

• 23andMe Adds New African Ethnolinguistic Groups to Ancestry Composition (23andme, 2022)

Of course this new feature on 23andme, based on matching strength, is not perfectly flawless or without its inherent limitations. And to be sure the possibility of learning more about the specifics of your African ancestry by looking for African DNA matches has been around for several years already (see this overview). However the novelty of this update lies in the robust manner in which your DNA is being compared to a wide array of 25 historically plausible populations to indicate the ethnic origins of (some) of your African ancestors. This is an ambitious endeavor which has been greatly anticipated by so many people throughout the years! Bringing to life a regional African breakdown which was often experienced as being too basic and incomplete.² Although from my assessment actually many valuable insights can also be derived from regional admixture, when interpreted correctly (see this overview).

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Figure 1 (click to enlarge)

A representative selection of updated 23andme results for Africans across the continent. I have seen more than 50 updated results from mainland Africa so far. Based on those results I am quite sure that this feature is pretty accurate. Because usually the outcomes are corresponding with the known ethnic backgrounds of African 23andme testers. As always unrealistic expectations about “100% accuracy” should be avoided. And to be sure 23andme doesn’t always “get it right”. But this update certainly can be considered as a huge step forward in pinpointing African lineage!

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Despite a few shortcomings I am very excited about this update on 23andme! Because based on more than 50 updated results for Africans I am quite impressed with the accuracy of this tool. Also the results I have seen for 50 Cape Verdeans and 100 African Americans are actually in line with historical plausibility. This blogpost series is therefore intended as a first introduction. In future blogposts I will follow-up with more details on the implications of these ethnic group matches within Africa! In fact I will also edit this blogpost itself with more information in the upcoming weeks (especially footnotes). So you might want to check that out too by revisiting this blogpost.

Right now the odds of obtaining one of the 25 ethno-linguistic groups are rather low for most people. Depending also on your background. For many people 23andme is simply not able to detect a sufficient level of matching strength. Which is inevitable given the limitations of 23andme’s African reference database.³ Understandably this may come as a big disappointment. However don’t despair because this update is a work in progress and upcoming updates will eventually reach more people!

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Table 1 (click to enlarge)

This chart shows that only 21 out of 100 of my African American survey participants received any ethnic group match (a few received more than 1). Hence the odds of receiving this update (~20%) are not that high. But still it is already a clear improvement when compared with the odds of receiving a match for an African country by way of 23andme’s Recent Ancestor Location tool. Based on a previous survey of mine this was only 3% for African Americans (see this overview).

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In the remaining part of this blog post I will discuss the following:

1. Disclaimers
   • Not intended to be conclusive! Ethnic identities are fluid and contextdependent.
   • Keep in mind implied timeframe.
   • Focus on complementarity of DNA matches and regional admixture
   • Educate yourself on historically plausible ethnic origins
2. How accurate is this update?
   • Updated results for 50+ Africans

In part 2 of this blogpost I will discuss my survey findings for 100 African Americans and 50 Cape Verdeans. Furthermore I will also post screenshots of updated results from other parts of the Afro-Diaspora.

• New Update on 23andme: Ethnic Group Matches within Africa! (part 2) 

Are African Americans really mostly “Nigerian”?

Last year 23andme’s research team published a major landmark study titled “Genetic Consequences of the Transatlantic Slave Trade in the Americas“. Arguably the largest DNA study to examine African ancestry in the Americas! Covering a wide span of the Afro-Diaspora, incl. also several thousands of African Americans. Highly interesting therefore. The research approach of this study consists of combining genetic data obtained from 23andme customers with Trans-Atlantic Slave Trade patterns. Which is practically the same approach I have been using ever since I started my AncestryDNA survey in 2013. This study by 23andme is even including Cape Verdean samples as a control group! Which is something I have done as well in all my research sofar.¹ Since I have recently finished my survey findings based on 23andme results (2018/2019 version) it should be useful to compare notes.

23andme’s 2020 study

• Genetic Consequences of the Transatlantic Slave Trade in the Americas (Micheletti et al., 2020)
• Supplemental Data Micheletti et al, 2020
• Table S7. Mean Ancestry Composition for the Research Cohort (main source for comparison) 

My own survey findings based on 23andme and AncestryDNA results

• Afro-Diaspora AncestryDNA results: A Comparison (Fonte Felipe, 2016)
• Update: Afro-Diasporan AncestryDNA Survey (part 1) & part 2) (Fonte Felipe, 2018)
• 23andme’s African breakdown put to the test: Afro Diaspora edition! (Fonte Felipe, 2021)

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Table 1 (click to enlarge)

This overview is showing the scaled African breakdown for the combined USA sample group (n=5785) featured in Micheletti et al. (2020). As well as for my own African American survey group (n=200). Despite smaller sample size actually very similar outcomes. Providing mutual corroboration. As can be seen “Nigerian” was clearly the most significant region. Going by group averages around 35%. Usually “Nigerian” is appearing as primary African category (162/200=81% in my survey). But even so “Nigerian” is still far from being predominant (>50%). Especially “Ghanaian, Liberian & Sierra Leonean” is also showing up as a substantial component. Furthermore regional scores indicative of Senegambian and Central African DNA are still considerable and nearly at 10%, on average. Making for an overall varied and rather balanced African breakdown. Do notice as well that around 20% of the African breakdown is falling in one of the “Broadly” categories!

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In this blogpost I will compare my own research findings (based on regional admixture) with 23andme’s study from 2020. In fact much of the data contained in 23andme’s study (based on the 2018 version of Ancestry Composition) is consistent with my own. As demonstrated above in Table 1. Which features the African breakdown for African Americans on 23andme (scaled to 100%).² Despite smaller sample size on my part actually very similar outcomes. Providing mutual corroboration. The study’s main findings of lower Senegambian and higher Nigerian ancestry than expected for African Americans are in line with what I had already established in my 2015 survey. Based on AncestryDNA test results for 350 African Americans. As well as more recently in my 23andme survey. See also:

• 350 African American AncestryDNA results (2015)
• 200 African American 23andme results (2018/2019 version)

Within the remaining part of this blog post I will discuss the following:

1. Why do so many African Americans have Nigerian ancestry?
   • Ancestral implications of “Nigerian” go beyond modern-day borders
   • Domestic Slave Trade from mostly Virginia spreading Bight of Biafra lineage
   • Lower Senegambian than expected because of less reproduction?
   • Substructure according to state origins
2. African breakdown for other parts of the Afro-Diaspora 
   • Mostly in agreement with historical expectations
   • Overlap & differences with my own survey findings
   • Regional diversity and substructure
   • Confirmation of Upper Guinean Founding Effect?
3. Discordances & limitations of 23andme’s study
   • Afro-descended samples taken from migrants underrepresent wider variation in countries of origin
   • Central African IBD disproportionately high when contrasted with regional admixture from Central Africa 
   • Sex-biased admixture: multiple & context-dependent historical narratives! 
4. Exciting future prospects:  personalized 23andme results featuring African IBD specified according to ethnic groups

Gullah Genetics

I have published another new page within the 23andme section of my blog. It features my survey findings based on 100 23andme results as well as 68 AncestryDNA results for African Americans with deep roots from South Carolina. Incl. several Gullah persons! Most of my findings are in agreement with previous published studies on African American genetics. In line with expectations Rice Coast related DNA seems to be more elevated indeed among South Carolinians.¹ As indicated firstmost by a high frequency of primary “Ghanaian, Liberian & Sierra Leonean” scores on 23andme. As well as prominent “Mali” scores on Ancestry. But in fact also Central African lineage and strictly Senegambian²ancestry appear to be more pronounced in South Carolina than elsewhere in the USA. To be sure Nigerian (related) ancestry is very common in South Carolina too but intriguingly it seems to be relatively subdued among Gullah persons.

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Table 1 (click to enlarge)

This overview is exploring regional substructure between various parts of South Carolina. Obviously only preliminary due to minimal sample size. However already a very insightful constrast between coastal and inland areas is surfacing. The Lowcountry and Pee Dee clearly having relatively elevated group averages for “Senegambian & Guinean” and especially “Ghanaian, Liberian and Sierra Leonean”. While “Nigerian” scores are much more prominent in Upstate and Midlands. Intriguingly the substantial Central African level showing up in coastal areas is also maintained into Midlands.

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My analysis is also zooming into coastal areas and contrasting with inland areas within South Carolina. And this kind of granularity might be a first when compared with other research projects (along with the inclusion of Southeast Asian admixture statistics). Atleast as far as I know and also when dealing with regional admixture within Africa as well (otherwise see Parra et al. (2001) for a truly pioneering study). Such a comparison is particularly insightful when wanting to grasp the localized formation of the Gullah people in the Lowcountry and adjacent Pee Dee area! In order to avoid any assumptions being made on my part I will not use Gullah as a synonym for people from the Lowcountry and/or Pee Dee.³ Although of course this is the main area where they are located. Follow the link below for fully detailed analysis, references and screenshots (incl. also AncestryDNA results):

• 100 South Carolina 23andme results

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Genetic Landscape of Gullah African Americans (Zimmerman et al., 2020)

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“Relative to southeastern non-Gullah African Americans, the Gullah exhibit higher mean African ancestry, lower European admixture, a similarly small Native American contribution” […]

“Despite a slightly higher relatedness to Sierra Leone, our data demonstrate that the Gullah are genetically related to many West African populations.” 

“This study confirms that subtle differences in African American population structure exist at finer regional levels. Such observations can help to […] guide the interpretation of genetic data used by African Americans seeking to explore ancestral identities.” (Zimmerman et al., 2020)

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• Genetic Landscape of Gullah African Americans (Zimmerman et al., 2020)

In this blogpost I will compare my own research findings with a very interesting recent study on Gullah genetics. This paper, linked above, is currently still in preprint. But it is consistent with several of my own research outcomes. Especially in regards to the quotes above. Impressively the study is based on the autosomal DNA results of 883 unrelated Gullah African Americans! A much larger sample size than I was able to use therefore.

However due to differences in methodology regrettably its potential for breakthrough insights is not fully realized. Resulting in less regionally detailed outcomes than I was able to obtain with my surveys based on 23andme and Ancestry results. To their credit the authors of the study largely succeed in sketching an appropriate historical framework for properly contextualizing their research outcomes. But at times essential details are still lacking while some of the information given appears to be outdated or not well referenced. Within the remaining part of this current blog post I will discuss the following:

1. Summary of my own survey findings based on 23andme and AncestryDNA results
2. Review of Genetic Landscape of Gullah African Americans (Zimmerman et al.; 2020)
3. African DNA matching patterns, beneficial for creating your own narrative about your personal African roots!
4. Screenshots of 23andme & Ancestry results for African Americans from South Carolina

23andme’s African breakdown put to the test: Afro Diaspora edition!

In the last couple of years 23andme has implemented several updates. Often beneficial for Tracing African Roots! Starting with the introduction of a new African regional framework in 2018. Finally providing a meaningful breakdown of West & Central African ancestry! Soon afterwards I started a survey of 23andme results among Africans as well as African Americans and other Afro-descended nationalities.¹ Similar to my previous Ancestry surveys my main research goal has always been to establish how much these results on an aggregated group level can already (despite limitations of sample size and other shortcomings) be correlated with whatever is known about the documented regional African roots for each nationality. As well as to improve correct interpretation of personal results.

Two years ago in February 2019 I published the first part of my examination of 23andme’s African breakdown. Which was based on my surveyfindings for 173 African 23andme testers from 31 countries (see this blog post). My 23andme survey has been ongoing till 23andme’s update in October 2019.² Because of other projects I have not been able to process my entire data-set earlier. But in this blog post I will at last present my main 23andme survey findings based on 889 results from 28 different countries across the Afro-Diaspora! Actually I have already analyzed these results in greater detail (incl. screenshots of individual results) on these pages:

• African American 23andme results
• Brazilian 23andme results
• Cape Verdean 23andme results
• Dominican 23andme results
• Haitian 23andme results
• Hispanic 23andme results
• Jamaican 23andme results
• Puerto Rican 23andme results
• West Indian 23andme results

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Figure 1 (click to enlarge)

A small selection of 23andme results from across the Afro-Diaspora.  Most of the outcomes are roughly corresponding with documented African roots  for each of my survey groups. Unrealistic expectations about “100% accuracy” as well as counter-productive obsessing about regional labeling should be avoided. Instead focus on what ever informational value you can obtain despite imperfections. Take notice as well how the additional Recent Ancestor Locations are on point!

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To summarize: I do indeed believe that 23andme’s African breakdown has passed the test! Although obviously there are several shortcomings to take into account. Based on both my African and Afro-Diasporan surveyfindings I find it quite impressive though that 23andme is often able to describe a person’s African origins in a meaningful regional framework. Which will usually quite closely correspond with either known genealogy or historical plausibility. The additional non-African scores and Recent Ancestral Locations actually reinforcing the robustness of 23andme’s predictions. In the remaining part of this blog post I will discuss the following:

1. African Breakdown
   • Main outcomes
     • Upper Guinean Founding Effect for Hispanic Americans
     • Virginia’s African roots most impactful on African American overall genepool?
     • Meaningful differentiation between Anglo-Caribbeans, Dutch Caribbeans and Garifuna
   • Frequency of primary African regions
   • Historical plausibility
2. Substructure
   • African Americans, Brazilians, Cape Verdeans, Haitians, Hispanic Americans, West Indians
3. Continental Breakdown
   • Southeast Asian admixture indicative of Madagascar connection
4. Recent Ancestor Locations:
   • Pinpointing African lineage
   • Cross-Diaspora connections
5. Screenshots 
   • Distinctive results across the Diaspora
   • Similar results across the Diaspora
   • Underrepresented parts of the Afro-Diaspora
   • Hispanic results reflecting Upper Guinean Founding Effect
   • Partially Cape Verdean results

ROOTSTECH 25–27 FEBRUARY 2021: Don’t Miss It!

For those who are not aware: ROOTSTECH Connect is the world’s largest family-history technology conference. And this year it will be a completely FREE and VIRTUAL experience! Hundreds of amazing sessions will be available online during and also after RootsTech Connect has ended on February 27th! Many of those sessions will offer precious insight for Africans and Afro-descendants in their quest to Trace African Roots! All it takes to attend is a free online registration. Right now more than 315,000 participants from more than 200 countries and territories worldwide have already registered! For more details:

• ROOTSTECH CONNECT 2021 
• Classes for Africans by Africans (series)
• Discovering African Ancestry through DNA (series)
• Ethnic Filters and DNA Matches: The Way Forward to Finding Your Lineage! (my own presentation!)

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I am very honoured, grateful and excited to also be part of this tremendous event! Because I will be giving an presentation as well! I will be demonstrating my scanning and filtering method to zoom into African matches or any other type of lineage you are interested in researching. I originally devised this technique in 2017. And I have been using it ever since to conduct my ongoing African DNA matches surveys. After registering for ROOTSTECH you should be able to find my class listed in the various search menus. But you can also just directly see it by following the link provided above.

If you are having trouble finding your African DNA cousins this can hopefully offer you a great opportunity to systematically look for your African DNA matches! During the event there will be an occasion to ask any questions by way of a chatroom. But of course you can also always reach me here on my blog if anything needs clarification or just to leave a comment. See also:

• How to find those elusive African DNA matches on Ancestry 
• African DNA Matching Patterns

In the remaining part of this blog post I will show a few slides for a sneak preview 😉 Furthermore I will also provide all materials/links mentioned during my presentation. For those intending to watch my presentation: Thank you for your attention! I will be rooting for you that the ethnic filtering method I have discussed will be beneficial for you as well! 

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Let’s get this cocktail party started! 😉

200 African American 23andme results

I have just published a new page within the 23andme section of my blog. It features my survey findings for 200 African American 23andme results. Various themes/topics are discussed. Especially delving deeper into the African breakdown but also highlighting a remarkably widespread Madagascar Connection for my African American survey group! Follow the link below for fully detailed analysis, references and screenshots:

• 200 African American 23andme results

Of course my 23andme survey may have several limitations. The group averages I have calculated for my survey-(sub)groups are neither absolute or conclusive but rather to be seen as indicative. One main aspect to take to heart is that there will always be individual variation around the mean! Still the sample size of n=200 should be sufficiently robust to pick up on the main tendencies. I have made an extra effort to do justice to the entire African American spectrum across the country. Of course all done on a best-effort basis.

Continental breakdown

Table 1 (click to enlarge) 

Generally speaking most African Americans are clearly of predominant African descent, combined with minor other ancestral components. Almost all of this additional ancestry will usually be European in fact. Often to a minor but still substantial degree. Aside from much more diluted but still distinctive amounts of especially Native American and perhaps more surprisingly also Southeast Asian admixture! See this screenshot for an overview of my previous Ancestry survey findings (n=350). And also this one featuring the complete continental breakdown (n=200). The overall group averages being nearly identical!

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At the same time I have also focused on gathering atleast a minimum number of 20 survey participants each for Louisiana, South Carolina and Virginia. These are 3 key states when considering African American genetics & origins.

Table 2 (click to enlarge)

The state origins of my survey participants are not based on a 4 grandparents criterium per se. But often this was indeed confirmed by their profile details on 23andme. Either way insightful variation according to state origins. Take notice especially of the highest subgroup averages which have been highlighted in red. The African admixture ranges (min. – max.) were as follows: Louisiana (51%-94%); South Carolina (75%-99%) ; Virginia (56%-94%). Compare also with my previous survey findings on Ancestry.

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Chart 1 (click to enlarge)

This chart is showing the full extent of African ancestry among my African American survey participants. The most frequent African admixture interval is 80-90%.  Which is the same as it was during my  previous Ancestry survey (n=350, see this chart).

Update of 23andme’s African breakdown

After a long delay of any meaningful improvements 23andme has actually implemented several updates in the last two years. Often beneficial for Tracing African Roots! Starting with the introduction of a new African regional framework in 2018. In 2019 new reference samples were added for especially North Africa. While also the potentially very useful Recent Ancestor Locations feature has been greatly expanded. In this year 23andme has decided to upgrade their customized algorithm. Unlike the 2019 update this upgrade is poised to have a considerable impact on 23andme’s African breakdown. 

Not per se in a positive way though. As it seems that 23andme’s algorithm tends to be “over-smoothing”. That is to say it will tend to homogenize people’s DNA in just a few categories.¹ As always one needs to refrain from being overly dismissive in order to also capitalize on any positive aspects. From what I have seen sofar this update does seem to be an improvement for many Afro-descendants, at least on balance. Of course I would need to see more updated results for a more substantiated judgement. For more details read:

• The 23andMe Ancestry Algorithm Gets an Upgrade (Oct. 2020)

Figure 1 (click to enlarge)

General trends of changes after 23andme’s update. According to 23andme (see this link).  The decrease in “unassigned” and most of the “broadly” categories is certainly observable. And especially within the European breakdown this will often be an improvement for Hispanics and African Americans. From what I have seen sofar actually an increase of “Nigerian” is not always happening for African Americans, or only marginally so. Also “Broadly West African” does not seem to change that much. But in particular “Angolan & Congolese” might often show a considerable increase. Often it seems at the expense of “Broadly Sub-Saharan African”.

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Either way it seems that this upgrade is likely to be rolled out to everyone and not just so-called V-5 customers. That is to say regardless of when you tested 23andme is aiming to eventually update your results using their new algorithm. At the latest early next year, 2021. Initially there was some confusion on whether “old” customers of 23andme (genotyped on the v1-v4 chips) would also receive this update. However quite recently 23andme’s customer service made this clarifying statement on 23andme’s forum:

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“In October of this year, we completed testing and validating the updated algorithm for the latest genotyping platform (v5) and decided to release this update to v5 customers while continuing to work on testing and validating the updated algorithm for previous genotyping platforms (v1 through v4). These processes are independent: the set of variants tested on the v5 genotyping chip is different from the set tested on prior chips. This means that updates for customers on current and previous chips require independent research, testing, and validation. While we cannot guarantee that the new algorithm will pass quality control checks when applied to earlier genotyping platforms, we hope to provide this update to pre-v5 customers by early next year“. (source, or see also this screenshot for complete statement)

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For the sake of correct interpretation of 23andme’s African breakdown I performed a comprehensive survey among African 23andme testers from all over the continent in 2019. This survey (based on 23andme’s 2018/2019 version) was ongoing up till now. At this point my African 23andme survey includes 314 people from 36 countries! By looking into their group averages you can get a pretty good idea on how well 23andme is able to describe the African origins of people who are already aware of their specific African lineage. Because I have been able to expand my survey I can now comment in greater detail about the predictive accuracy of 23andme’s African breakdown (2018/2019 version). Beyond what I had already established in 2019.² In the remaining part of this blog post I will discuss the following:

1. African surveyfindings (2018-2019 version)
   • “Nigerian” also partially describes Ewe lineage from Ghana 
   • “Angolan & Congolese” is not always fully covering Central African DNA 
   • “Sudanese” is also being reported for Sahellian West Africans, incl. Tuareg
2. Screenshots before & after 2019 update (Africans & Afro-descendants)
3. Screenshots before & after 2020 update (Africans & Afro-descendants)

Slave Voyages: not only Trans-Atlantic but also Intra-American!

This blogpost is mainly intended to announce a major overhaul for one of the most important sections on my blog:

• Regional Origins of the Afro-Diaspora according to Documented Slave Trade Patterns

The page referred to above is now featuring new screenshots taken from the invaluable Trans-Atlantic Slave Trade Database as well as the additional Intra-American Slave Trade Database. Reflecting the current state of knowledge. I am convinced that the data contained on that page can be very educational and useful for anyone wanting to learn more about their African roots. Just as long as you keep in mind inherent limitations and inform yourself about the relevant context. This kind of aggregated information is probably most useful on a population level.¹ But also for your personal quest it can provide you with a very valuable starting point! In particular in order to judge the historical plausibility of any DNA test results you may have received. Not only regional admixture or haplogroups but also African DNA matches. And even DNA matches from across the Afro-Diaspora!²

***(click to enlarge)

Despite its limitations the Trans-Atlantic Slave Trade Database (TAST) is simply the most comprehensive and up-to-date resource available when wanting to look into Trans-Atlantic Slave Trade patterns. The website was updated in 2019. It now includes information about more than 36,000 Trans-Atlantic slave voyages! See also this recommendation by Henry Louis Gates.

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““If there were a Pulitzer Prize given for historical databases, the Transatlantic Slave Trade Database would win it, hands down,” says Gates, Alphonse Fletcher University Professor at Harvard.” (source)

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I myself have often relied heavily on the Trans-Atlantic Slave Trade Database as some sort of baseline. To establish historical plausibility within my ongoing research efforts on how personal DNA test results of Afro-Diasporans may already be in alignment with historical expectations. See also:

• AncestryDNA Surveys (2013-2018)
  • Documented African origins confirmed on group level? (2016) (scroll down to section 4)
  • Afro-Diasporan AncestryDNA Survey (part 1) (2018)
• 23andme surveys (2019-ongoing)
• African DNA Matching Patterns (2017-ongoing)

It can be very tempting to correlate slave trade records with population genetics or assumed ethnic/regional origins of Afro-descended populations. Given the absence of more straightforward information. But such an approach can hold many pitfalls. Even if the Slave Voyages database is deemed to provide nearly fully coverage for any particular country. This is because you cannot just simply assume that there will be a direct extrapolation from the data at hand. Reality is too complex regrettably. Several factors need to be taken into account. Mainly to do with incomplete knowledge about the demographic evolution of enslaved Africans and their descendants. See the updated section for more detailed discussion. This aspect might be most pertinent:

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• Intra-American Slave Trade, Domestic overland Slave Trade and Post Slavery migrations have resulted in great deal of additional intermingling and diversification of African lineage. This is especially true for the USA and Brazil because of their continental size. But in fact also for most parts of the Caribbean and Latin America.

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Table 1 (click to enlarge)

Based on these estimates (taken from O’Malley, 2009),  Intra-American Slave Trade for North America was around 15%. The actual shares per state do show important variation. For Virginia and South Carolina this share of slave trade by way of the Caribbean is  quite minor: around 10%. However for other states it is more substantial. Do keep in mind though that Domestic (overland) Slave Trade is not taken into account. While actually going by sheer numbers this type of Slave Trade was most significant for the USA. An estimated 1 million enslaved African Americans (often with Virginia background) are known to have been victimized by the so-called Second Middle Passage (see this link).

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Obviously there will be other factors as well that could explain genetic results being disproportionate to what you might expect based on slave trade data. Substructure within any given Afro-descended population also being highly relevant. This is something which I have blogged about several times already and also in upcoming blog posts I will return to this important topic. Within the remaining part of this current blog post I will discuss the following:

1. Trans-Atlantic Slave Trade Database
   • Newly added Portuguese & Spanish Slave Voyages (1500’s) corroborate Upper Guinean founding effect for many Hispanic Americans
2. Intra-American Slave Trade Database
   • Disclaimers
   • Intra-American Slave Trade Patterns for the USA
3. Final Passages: The Intercolonial Slave Trade of British America, 1619-1807 (G. E. O’Malley, 2014)
   • Excellent research. I will feature some key insights and overviews from this highly recommended book.