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

My own survey findings based on 23andme and AncestryDNA results

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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:

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 Continue reading

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:

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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

Continue reading

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:

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

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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:

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)

“Ivory Coast/Ghana” also describes Liberian DNA

I have created a new page featuring the AncestryDNA results for West Africans from the following countries: Liberia, Ivory Coast, Burkina Faso, Ghana, Togo & Benin. I will create a new section for the remaining part of West Africa (Upper Guinea) shortly. The number of results I have collected so far might be minimal but already my survey findings turn out to be quite insightful. I also provide some statistical data, analysis and relevant context. Follow this link to view the page:

In addition I also discuss the implications these findings might have for Afro-Diasporans in an attempt to improve proper interpretation of their West African regional scores, in particular for “Ivory Coast/Ghana” and “Benin/Togo”. One of these implications I will also discuss in greater detail in this blog post:

“Ivory Coast/Ghana” is also predictive of Liberian & Sierra Leonean DNA

The socalled “Ivory Coast/Ghana” region is indeed quite predictive of both Ghanaian and Ivorian origins. However in addition ancestry from Liberia and to a lesser degree (southern) Sierra Leone might also be described by this region. You will need to perform your own follow-up research in order to find out more specifics.

Map 1 (click to enlarge)

IvcGhana region

Source: ancestry.com. (text in red added by myself)

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Chart 1 (click to enlarge) 

Stats (GH=22)

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Continue reading

ROOTS.NL (S1E3) – True Colours (Dutch Race Relations)

2408_CoverGen_7-1

Cover of Dutch Genealogy magazine in which Annemieke’s research was featured in 2015. The portrait is of a Dutch Countess with her African servant named Cocquamar Crenequie.

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“ The exhibition “From the Shadows, new light on African servants at Weesper notables,” opened at the Weesp Museum to a small crowd of townspeople on March 25, fittingly one day before the International Day of Remembrance of the Victims of Slavery and the Transatlantic Slave Trade. It aims to confront Dutch people with the possibility that their history contains more nuances than they are probably aware of.” […]

Another prominent figure who appears in the exhibition is Christiaan van der Vegt, servant in the 18th century to Weesp mayor Abraham D’Arrest. What Christiaan’s African name was and how he ended up in the town is unknown, but he had married a girl from Weesp and they had ten children. “Imagine the surprise of (white) Dutch woman Annemieke van der Vegt when she in 2013 – 250 years later – unsuspectedly decided to research her past and came to find that she is a direct descendant of this African servant.” (Daily Herald Sint Maarten, april 4th 2017)

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In the previous parts of my blogseries about Annemieke van der Vegt and her search for her West African forefather (Christiaan van der Vegt, ca.1750-1825) I have already discussed the following topics:

In this third part I will attempt to shed more light on the following question: how does Christiaan’s life story fit in the currentday discussions on race relations within Dutch society? I will also include other known cases of African or Afro-descended persons living in the Netherlands before the 1900’s. Specifically I will deal with the hotly debated “Zwarte Piet” topic and the origins of this increasingly contested figure of Dutch folklore. Lastly I will describe the potential role DNA testing might play in uncovering the genetic legacy of the colonial past of the Netherlands. Not only for Dutch people but also across the Afro-Diaspora and even within Africa.

  1. Seeking a broader context for Annemieke’s research
    • Weesp & its Ghanaian connection
    • African presence in the Netherlands earlier than imagined?
  2. Tracing the Roots of “Zwarte Piet”
    • Were African servants such as Christiaan the inspiration for Zwarte Piet?
    • Dutch Tolerance showing true colours?
    • Amsterdam leading the pack (again)?
    • My personal perspective on Christiaan’s lifestory
  3. Dutch colonial legacy revealed by DNA testing & genealogy
    • African ancestry among (ethnic) Dutch people
    • Dutch ancestry across the Afro-Diaspora
    • Dutch ancestry in Ghana

Continue reading

ROOTS.NL (S1E2) – Searching for Gold

This is the second post in my blogseries about a Dutch woman (Annemieke van der Vegt) who is in an ongoing search for her West African forefather (named Christiaan van der Vegt after his baptization in 1777). In the first post I discussed how AncestryDNA can be very helpful when trying to trace African ancestry. It provided Annemieke with conclusive evidence of her African genetic inheritance. Furthermore I gave an overview of Annemiekes astonishing archival research findings sofar. Follow these links for more details:

Many fascinating details about Christiaan’s life have been uncovered by Annemieke already. The one thing she is still very eager to discover though is his original name given to him by his parents. And also his ethnic identity before getting caught up in the slave trade as a child and being forcibly relocated to the Netherlands. This blog post will therefore be centered around the question facing not only Annemieke but many Afro-descendants in the Diaspora: Is it possible to pinpoint a plausible ethnic origin for one’s African bloodline?

***Map 1 (click to enlarge)

Nsoko

Man from Ivory Coast (source) & map of Ghana showing locations of historical gold trading cities of Nsoko and Begho.

Continue reading

ROOTS.NL (S1E1) – Dutch woman in search for West African forefather

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AncestryDNA results of a Dutch person with one single African ancestor, Christiaan van der Vegt, possibly depicted in the drawing (c. 1760) to the left.

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“Christiaan was born around 1743. This I know by his letter from 1815: (translated from Dutch)

“Letting you gratefully know Christiaan van der Vecht, born at the Coast of Guinea, 73 years of age and living in Weesp.”

Where at the Coast of Guinea he was born I don’t know and also how he came to the Netherlands is unknown to me.”

My name is Annemieke van der Vegt and I am a grand-, grand-, grand-, granddaughter (his grand-, grandson is my grand-, grandfather) of Christiaan van der Vegt”

For the complete story see: What was Christiaan’s name?

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In this blog post and two following ones i will feature the highly remarkable research findings of a Dutch woman who is in an ongoing search for her West African forefather. By simply googling her surname in 1998 she discovered that she had a West African ancestor she was previously unaware of!  She found out eventually by way of archival research that her West African forefather had been a personal servant of several members of the Dutch royal family of Orange-Nassau (at the time of his employment the Netherlands were still a Republic though). And later on (c. 1765) he was also a servant of the mayor of Weesp, a small town near Amsterdam. Most likely he had been only a child when he was brought to the Netherlands. As an adult he had several other jobs and married a Dutch woman with whom he had 10 children. He was baptized as Christiaan van der Vegt in 1777. His original African name and African ethnic identity remain unknown for now but his Dutch ggg-granddaughter, Annemieke van der Vegt, is determined to find out.

The strongly personal motivation of this sixth generation Dutch descendant to uncover the life story of her West African forefather is very inspirational. At the same time her astoundingly diligent research is proving to also have great relevance for many other people. Her work has been put in the spotlight in several Dutch media articles already, incl. the national newspaper Volkskrant, as well as a national genealogy journal. The Weesp museum has recently held a special exposition about Christiaan and three other Dutch Africans who are known to have lived in Weesp around the same time (mid 1700’s). Also historians (both within the Netherlands and internationally) are eager to tap into her specialized field of knowledge which she has been steadily compiling on her amazing blog since 2013. This was the year that marked the 150th anniversary of Dutch abolition of slavery in 1863.

If you continue reading i will discuss the following topics:

  1. What can be learnt from AncestryDNA when trying to trace African ancestry? (ROOTS.NL, part 1)
  2. Is it possible to find a plausible ethnic background for Christiaan? (ROOTS.NL, part 2, Searching for Gold)
  3. How does Christiaan’s life story relate to the currentday discussions on racism within Dutch society? (ROOTS.NL, part 3, True Colours) Continue reading

Specifying the African Origins of the Afro Diasporan Genome (part 2)

Schroeder et al. (2015) Fig1 B&C

Genome-wide ancestry of 17th-century enslaved Africans from the Caribbean (Schroeder et al., 2015)

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“The transatlantic slave trade resulted in the forced movement of over 12 million Africans to the Americas. Although many coastal shipping points are known, they do not necessarily reflect the slaves’ actual ethnic or geographic origins. We obtained genome-wide data from 17th-century remains of three enslaved individuals who died on the Caribbean island of Saint Martin and use them to identify their genetic origins in Africa, with far greater precision than previously thought possible. The study demonstrates that genomic data can be used to trace the genetic ancestry of long-dead individuals, a finding that has important implications for archeology, especially in cases where historical information is missing.” (Schroeder et al., 2015, p.3669)

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Continue reading

Guyanese Slave Census of 1819 , less specified but still representative?

Berbice (Guyana) Slave Census of 1819

SUMMARY

Number of slaves 23,881
Creole (i.e. born in the Americas) 10,954 (46% of total)
African 12,867 (54% of total)
African specified ethnically/regionally 1,198 (5% of total)

BREAKDOWN OF AFRICAN BORN SLAVES

Kongo (Congo) 212 – 18% of African specified
Coromantee (Ghana) 139 – 12% of African specified
Popo (Benin/Togo) 113 – 9% of African specified
Source

Origins of African-born slaves Berbice 1819 Continue reading