Category Archives: DNA Studies

The Admixture Histories of Cabo Verde: New DNA Studies!

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Cape Verde’s football team, a.k.a. Tubarões Azuis (The Blue Sharks), almost reached the semi-finals of the Africa Cup this year. Never mind being a “small” nation of around 1 million people (islands + diaspora). Cape Verdean team spirit, talent and guts are widely acclaimed! It must be in the genes 😉

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Ever since I got my first DNA test results in 2010 I have been researching my Cape Verdean roots from several angels. Of course everything starts with personal genealogy. But for deeper understanding I also take into account: population genetics, historical demography and cultural retention. In 2014 I created a separate website for this purpose: CVRAIZ: Specifying The African Ethnic Origins for Cape Verdeans. In 2015 (on this blog) I published my first survey findings based on Cape Verdean personal DNA test results. Furthermore I have always been applying a comparative analysis to see how Cape Verde fits in the broader picture of the Afro-Diaspora.1

In the last couple of years several new peer reviewed studies have been published using a similar research approach. So that makes it very interesting to compare notes with my own research findings! I will mainly focus on the most recent study “The Admixture Histories of Cabo Verde” (Laurent et al., 2023) (original title prior to peer review). But I will also refer to a few other studies.

The Admixture Histories of Cabo Verde (Laurent et al., 2023)

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“Cabo Verdean Kriolu is the first creole language of the TAST, born from contacts between the Portuguese language and a variety of African languages. The archipelago thus represents a unique opportunity to investigate, jointly, genetic and linguistic admixture histories and their interactions since the mid-15th century.” (Laurent et al., p.4).

“We find that admixture from continental Europe and Africa occurred first early during the TAST history, concomitantly with the successive settlement of each Cabo Verdean island between the 15th and the early 17th centuries”. (Laurent et al., p.26).

“Finally, we find that recent European and African admixture in Cabo Verde occurred mainly […] in the 1800s“. (Laurent et al., p.27).

“our results highlight both the unity and diversity of the genetic peopling and admixture histories of Cabo Verde islands […].” (Laurent et al., p.27)

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Figure 1 (click to enlarge)Fig. 1 IBD sharing (Korunes et al. 2022)Source: Korunes et al. (2022). This plot shows how there’s shared ancestry between all islands. Even when the degrees of kinship will naturally be greater on each separate island and also among certain subsets of islands. In particular the socalled NW cluster (a.k.a. Barlavento islands) and Boavista. Fogo is being mentioned as having the highest incidence of endogamy. While this study also confirms that Santiago is clearly the oldest population of the entire island group. Based purely on their DNA analysis but in fact in line with known history!

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Recent studies on Cape Verdean Genetics
My own research 

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I have been eagerly anticipating these most recent DNA studies on Cape Verdean genetics. And I am also very excited about the prospects for follow-up research. These new papers are firstmost a continuation of previous peer reviewed DNA studies about Cape Verde (see this link for an overview). In fact some outcomes repeat and reinforce my own earlier key findings (2011-2022).2 Still there are a few intriguing novelties as well. Providing meaningful insight.

I truly appreciate all the efforts of the research teams behind these studies. But I do have to point out that I have mixed feelings about the accuracy of the historical framework. Especially as provided by Laurent et al. (2023). This study seems to have overlooked an essential aspect of Cape Verde’s historical demography. Because most likely already in the late 1600’s a majority of the Cape Verdean population (both black and mixed-race) was no longer enslaved (see this table). Cape Verde is indeed part of the Atlantic Afro-Diaspora. And especially in its early history (1460-1660) Cape Verde was greatly impacted by the TAST (Trans-Atlantic Slave Trade). But several singular aspects about the Cape Verdean experience do require very careful and context-dependent analysis!

  1. Main outcomes
    • Genetic clustering of Cape Verdeans according to island origins.
    • Differentiation of African ancestry according to island origins.
      • Greater genetic affinity with Wolof samples among Barlavento islanders
      • Minor “Nigerian” and Central African lineage among Cape Verdeans
    • Various admixture pulses but all islands have substantial shared ancestry from the 1500’s.
  2. Getting the historical context right
    • Most Cape Verdeans (80+% of population) have been free of slavery since at least 1731
    • Other points of critique.
  3. Suggestions for future research
    • Sampling: apply criterium of 4 grandparents born on the same Cape Verdean island.
    • More granular analysis of non-Senegambian/Iberian origins: Sierra Leone, Sephardi Jewish, Goa etc..
    • New research agenda involving Cape Verdean Diaspora.

Continue reading →

Suriname’s African Roots: as manifested by DNA & Language!

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150 years Keti Koti: Breaking the Chains of Dutch Slavery!!!
This year Keti Koti will be a celebration of 150 years since Dutch slavery ended! Not only in Suriname but also for other former Dutch colonies in the Caribbean: Aruba, Bonaire, Curaçao, Saba, St. Eustatius, St. Maarten. Officially 1863 was the year that slavery was abolished in the Dutch Caribbean & Suriname. However many people practically remained enslaved for another ten years in order to “compensate” their former enslavers… See this website for the meaning of the year 1873. Photo credits: Hogeschool Rotterdam, Flickr1, Flickr2.

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Klik hier voor de Nederlandse versie van deze blogpost!

Keti Koti literally means “the chains are broken” in Sranan Tongo: the most spoken language of Suriname aside from Dutch. Keti Koti refers to emancipation from Dutch slavery. Annual celebrations and remembrance taking place on the first of July. Not only in Suriname itself but in the Netherlands as well. And also in the Dutch Antilles where they have several other names for the same event. This year will be a special Keti Koti because the Dutch government has declared a Slavery Memorial Year from 1 July 2023 to 1 July 2024.1 See also:

In honour of this fine day I thought it would be fitting to highlight some key research findings about the African roots of Surinamese Creoles & Marrons. I will just focus on what I happen to be aware of. Providing a summary of the main take-aways. But I intend to follow-up on this introductionary post.2 As always it should be kept in mind that this type of research is not intended to give the final say! It will not cover all grounds and of course future efforts might bring new or additional insight 😉 But I do believe that what has been uncovered sofar is already quite valuable. Especially from a holistic perspective.

From all places across the Atlantic Afro-Diaspora African cultural retention is probably the greatest in Suriname. And therefore the outcomes discussed should not be completely surprising. Although especially for younger generations these cultural legacies might no longer be widely known. Furthermore the link with specific modernday African countries such as Benin or Liberia might not be immediately clear for many people. Also for reasons of prestige perhaps some types of African lineage have traditionally been more emphasized than others. 

In fact there are several distinct groups of Afro-descendants in Suriname. Nowadays also called Afro-Surinamese when combined. But usually the main distinction being made is between largely urbanized Creoles for whom arguably Keti Koti is most relevant. And also the various so-called Marron peoples who famously escaped from slavery, many generations before 1863/1873!

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Contents of this blog post:

  1. DNA Studies
  2. Linguistic Studies
  3. Exciting new prospects to uncover African Identities for Dutch Caribbeans & Surinamese!

Continue reading →

Ancestry’s 2022 update: some bright spots, but too little too late!

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In this blog post I will provide a review of Ancestry’s latest update.1 As always I will keep my focus on the African breakdown featured in Ancestry’s so-called Ethnicity Estimate. In fact Ancestry has released several updates earlier this year. Eventhough some positive developments are taking place overall speaking I am not impressed. Because I just know that Ancestry is able to do so much more! It almost seems that Ancestry is going out of its way in order to avoid making any truly breakthrough update for their customers of West/Central African descent…

***ivc-ghana-updatedAncestry is introducing two new African regions with this update. These are however either minimal or absent for practically all Atlantic Afro-descendants. The good news is that the predictive accuracy of “Ivory Coast & Ghana” is finally being restored to its former level from the 2013-2018 version! At last providing a reasonable indication of DNA associated with that region and neighbouring countries (especially Liberia!). Something which Ancestry managed to screw up during their previous updates..

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My main qualm with Ancestry is that genetic communities for pinpointing West & Central African lineage are still missing! Even when earlier this year 23andme demonstrated that such a feature can be implemented already. Introducing no less than 25 ethnolinguistic genetic groups from Africa (see this blogseries). To be sure this tool based on matching strength is still a work in progress. But at least 23andme has set things in motion and stepped up their game! Something which Ancestry for some strange reason is still refusing to do…

Contents of this blog post:

  1. African breakdown for Africans after the 2022 update
    • Ancestry’s African Reference Panel
  2. African breakdown for Afro-descendants before and after the 2022 update
    • Best African breakdown since 2013-2018!
  3. Ethnicity Inheritance and Chromosome Painter
    • How can Ancestry finally take things to the next level?
  4. Screenshots of African updated results

Continue reading →

Are African Americans really mostly “Nigerian”?

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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 →

Gullah Genetics

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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):

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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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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

Continue reading →

200 African American 23andme results

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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:

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).

Continue reading →

Update of 23andme’s African breakdown

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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:

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)

Continue reading →

Ancestry’s new African Breakdown: merely cosmetic changes?

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Only a few weeks ago Ancestry went ahead with their ill-advised deletion of smaller DNA matches (6-8 cM). Resulting in a great loss of customer value. But already the next update is being rolled out. This time once again our Ethnicity Estimates are being reshuffled. It almost seems Ancestry is making it a yearly tradition to perform their ethnicity updates in the Autumn. Or should I say a yearly marketing ploy? Either way this is already the third time in a row! Starting with the first distastrous make-over of Ancestry’s African breakdown in 2018. Things did get better though in 2019. My verdict of last year was: “a step in the right direction but no substantial improvements for the most part. At least not when compared with the original African breakdown from the 2013-2018 version”. And really this assessment still stands also for this 2020 update. There have been a few positive changes, but nothing game changing. 

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Map and full listing of all the 12 African regions available on Ancestry after its 2020 update. Despite the renaming of  a few regions the only new region is “Southern Bantu”. This region will however be minimal or absent for practically all Trans Atlantic Afro-descendants.  Because of the restored “Ivory Coast/Ghana” region the West African breakdown is now more coherent than in 2019. However it still has several shortcomings…All in all nothing substantial to make up for the recent purge of smaller DNA matches.

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I find it disappointing that most of my suggestions for meaningful improvements (originally posted in 2018) have still not been taken up by Ancestry. Yet again this update seems to be centred mostly around providing greater regional resolution for Europe and Asia. The African breakdown seems to be merely a sideshow. The finer distinction to be made for Scottish ancestry is certainly striking but probably also overambitious.1 Such a focus is to be expected given that Ancestry’s customer database is overwhelmingly of European descent. While Asia probably represents a promising growth market. However the relative neglect of African & Afro-descended customer needs does go against Ancestry’s selfproclaimed goal to make their product experience inclusive for everyone. In my previous blog post I stated that Ancestry should seek to offer new tools geared to facilitate specialized research for Afro-descended customers. It should be clear that this update does NOT compensate for the loss of small African matches, earlier this month.

It is still my belief that each updated version as well as each separate DNA testing company should be judged on its own terms.2 For the sake of correct interpretation I have therefore yet again performed a comprehensive survey among 135 African Ancestry testers from all over the continent to evaluate the changes before and after this update. In addition I have also looked into a representative array of 50 updated results from across the Afro-Diaspora. These findings will be described in greater detail further below. Again for the most part no major changes. Which is why I will keep this discussion brief and only highlight the main outcomes:

  1. African breakdown for Africans before and after the 2020 update
  2. African breakdown for Afro-descendants before and after the 2020 update
  3. Is Ancestry getting sloppy?
    • When will we have genetic communities for West/Central Africa?
  4. Screenshots of African updated results

As always make an attempt to inform yourself properly without being overly dismissive. Despite shortcomings I do still think you can get valuable ancestral clues from Ancestry’s African breakdown. The macro-regional breakdown also to be taken into account to get a grasp on the greater picture. Instead of being preoccupied about the appearance of any surprising but minimal %’s. Which might very well disappear with the next update 😉 Such an approach to be combined with your remaining/salvaged African DNA matches, historical plausibility etc.. My previous discussion of the 2019 update may still offer helpful guidance. Ancestry’s FAQ is also useful:

Continue reading →

African DNA matches reported for 30 Jamaicans on Ancestry

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In this blog post I will analyze the African DNA matches being reported by Ancestry for 30 of my Jamaican survey participants.1 A follow-up to my previous blog post about 100 Jamaican AncestryDNA results (see this link). Most important finding arguably being that Nigerian & Ghanaian predominance in regional admixture (2013-2018 version) for Jamaicans is also reflected in their DNA matches. Notwithstanding recent updates on Ancestry 😉 Furthermore there is no longer any excuse NOT to be looking for African DNA matches. I found on average almost 30 African DNA matches for each one of my survey participants!!! There are plenty of Africans who have tested with Ancestry by now. So you only need to search for them and then you will be rewarded with greater insight and closer connection to your African heritage! See also these links:

Because I was given access to their profiles on Ancestry I was able to use my scanning and filtering method of DNA matches in Excel. Aside from African matches I will also be including Jewish and South Asian matches in my discussion. Below a statistical overview of my main findings. Going by group averages. For the individual results which do display greater variation follow this link:

Table 1 (click to enlarge)

Stats (n=30)

All of my 30 survey participants received African matches. Also I was able to find 5 close African matches (>20cM)! On average 29 African matches were reported for each person. Around 80% of all African matches are connected to either Nigeria (16/29) or Ghana (7/29). The African admixture averages are based on the old 2013-2018 version of AncestryDNA. As I believe that despite shortcomings this version still offers the best fit for Jamaica’s known regional roots within Africa (see this link). Calculation of average & maximum shared DNA is based on the outcomes per survey participant. In all other tables below it will be calculated based on all DNA matches taken together.

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Table 2 (click to enlarge)

Afro Matches

The background column is mostly based on informed speculation (plausible surnames/regional admixture) but at times also confirmed by public family trees. The proportion of West African (Lower Guinea) related matches is 87% (755/861) of all African matches. The high number of especially Nigerian Igbo matches is quite striking. Undoubtedly due to very substantial ancestral connections. But possibly also a bit inflated within this overall overview. Reflecting a greater popularity of DNA testing among Nigerians as well as Ghanaians when compared with other Africans. Francophone & Lusophone migrants still tend to be  greatly underrepresented in Ancestry’s customer database. In particular it seems from Central Africa as well as Benin & Togo.

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This project was merely intended as an exploratory exercise. Of course my research findings have limitations in several regards. And therefore they should be interpreted carefully in order not to jump to premature or even misleading conclusions. Still I do believe they can reveal relevant tendencies in African DNA matching patterns for Jamaicans in general. These outcomes may also provide valuable insight into the various ancestral components found within the Jamaican genepool. Contributing to answering major questions like: Do Jamaicans have more Nigerian or Ghanaian ancestry? In particular when aiming for complementarity by also taking into account admixture analysis, genealogy and relevant historical context.

Below an overview of the topics I will cover in this blog post:

  1. Considerations when dealing with DNA matches
  2. Combine DNA matches with admixture analysis for more insight
  3. West African matches: as expected Nigerian and Ghanaian DNA matches were clearly most numerous. Only a subdued number of matches from Upper Guinea. This outcome is roughly in agreement with a predominant Lower Guinean macro-regional share of around 70% I calculated for 100 Jamaicans, based on admixture (see this chart).
  4. Central & Southeast African matches: quite low in number. In contrast with often substantial “Cameroon/Congo” scores being reported for Jamaicans. Interestingly Cameroon is relatively well represented.
  5. Other African matches: unexpected & uncommon. Higher odds of false positives but in some cases to be corroborated by distinctive admixture?
  6. Substructure: are there any group differences according to admixture level, “genetic community” or parish?
  7. Jewish & South Asian matches: disproportionately numerous whenever backed up by associated admixture (even in trace amounts!)
  8. Methodology: describing how I filtered the African & non-African DNA matches as well as the decision rules I applied when determining a plausible background for each DNA match.

Continue reading →

Ancestry’s 2019 Update: Back on Track Again?

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Backontrack

Map showing all the regions available on Ancestry after its 2019 update. For Trans Atlantic Afro-descendants the most impactful changes seem to be that: “Nigeria” has been brought back to life again! But “Ghana” has been derailed. “Mali” is no longer overpowering “Senegal”, but it does include both Sierra Leone and Liberia now! See this link for a complete list of regions and genetic communities. Photo credits for top picture showing a train passing by a railway station in Ghana.

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Starting in October 2019 Ancestry has been rolling out a new update of their Ethnicity Estimates. As I have said before your DNA results are only as good as the next update. So it is best not to get too attached to them 😉 Given scientific advancements and a greater number of relevant reference samples one always hopes that a greater degree of accuracy may be obtained. But naturally no guarantees are given that this will indeed be the case. After all Ancestry’s update in 2018 arguably was a downgrade rather than providing any meaningful improvement! At least when it comes to the African breakdown. In regards to the European, Asian and Amerindian breakdown Ancestry seems to have made steady progress on most fronts. Continued also with this 2019 update.

From my experience the best indication of predictive accuracy is obtained by looking at how Africans themselves are being described when tested by Ancestry. Which is why I have performed a comprehensive survey among 136 African Ancestry testers from all over the continent to establish a more solid basis for judgement. In addition I have also looked into a representative array of 55 updated results from across the Afro-Diaspora. These findings will be described in greater detail further below. The outcomes are mostly positive for Africans themselves but more ambivalent for Afro-descendants. Probably because Ancestry’s algorithm is less adequate when describing the mixed and therefore more complex African lineage of the Afro-Diaspora. My overall verdict about this 2019 update: a step in the right direction but no substantial improvements for the most part. At least not when compared with the original African breakdown from the 2013-2018 version.

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Table 1 (click to enlarge)

Stats Afro

Based on the updated results for 121 African AncestryDNA testers from 30 countries, across the continent. Take notice that the predictive accuracy in most cases is quite solid. Although in a few cases it is still clearly in need of improvement. This goes especially for “Ghana” and “Eastern Bantu”. Follow this link for my spreadsheet containing all the individual results.

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Due to wild fluctuations in just two years many people might experience update fatigue. Some people will even be tempted to bash their DNA test results and admixture analysis in particular. But an overtly dismissive stance will be self-defeating and deprive you of informational value yet to be gained! As I have always argued that regional admixture DOES matter and Ancestry’s Ethnicity Estimates are of course NOT randomly determined.1 Ancestry’s predictions may not be 100% accurate but still in most cases they are reasonably well-aligned with the known backgrounds of my African survey participants. As can be verified from the overview above.

For those perplexed by all the changes do at least make an attempt to inform your self properly. Given how wrong Ancestry got it in 2018 (see this blog series) it is only natural that some grave flaws had to be rectified. Regrettably it seems in some aspects an over-correction did take place. Still depending on your background this update certainly also can be beneficial. Furthermore when considering your African breakdown in a macro-regional framework the changes have actually not been that drastic. And many things more or less remained consistent as I will discuss in section 3 of this blog post.

It has always been my belief that regional estimates require correct interpretation. And each updated version as well as each separate DNA testing company should therefore be judged on its own terms. Then again these admixture results can only take you that far. My advise is to also look into your African DNA matches, as well as historical plausibility and just plain genetic genealogy for greater combined insight. See also these links:

For those seeking deeper understanding of Ancestry’s 2019 update this blog post will attempt to take things further by having a closer look at:

  1. African breakdown for Africans before and after the 2019 update
  2. Ancestry’s Reference Panel & Algorithm
  3. African breakdown for Afro-descendants before and after the 2019 update
  4. Getting back on track again
  5. Screenshots of African updated results
  6. Poll on whether this update has been an improvement or not, please vote!

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