Tutsi probably differ genetically from the Hutu

By Razib Khan | August 29, 2011 11:04 pm


Paul Kagame with Barack and Michelle Obama

I first heard about Rwanda in the 1980s in relation to Dian Fossey’s work with mountain gorillas. The details around this were tragic enough, but obviously what happened in 1994 washed away the events dramatized in Gorillas in the Mist in terms of their scale and magnitude. That period was a time when the idea of “ancient hatreds” leading to internecine conflict was in the air. It was highlighted by the series of wars in the former Yugoslavia, and the Tutsi-Hutu civil wars in Rwanda, Burundi, and Congo. Of the latter the events in 1994 in Rwanda were only the most prominent and well known.

After having read Dancing in the Glory of Monsters: The Collapse of the Congo and the Great War of Africa I am relatively conscious of the broader canvas of what occurred in Central and East Africa in the 1990s. Not only was there a conflict between Tutsi and Hutu in Rwanda, but a similar dynamic also flared up in Burundi. The tensions are more complex in Congo and Uganda, in large part because there are many ethnic players, and the Hutu role as the antagonists with the Tutsi is divided among many different populations. In trying to distill the complex ethnography of this region in setting the structural parameters of the landscape into which the violence of the late 20th century emerged many pundits have pointed to the role of the Belgian colonial authorities in crystallizing, sharpening, and perhaps even originating the distinction between Tutsis and Hutus. This is not totally unreasonable if you don’t know much. A quick “look up” will confirm that there is no linguistic or religious distinction between the two groups; they share a common culture in many ways. Rather, the differences seem more of class and ecology. The Tutsi minority had a much stronger pastoral element to their economy. The Hutus were conventional farmers, clear legacies of the Bantu expansion which swept from West-Central Africa east and south, all the way to the Cape of Good Hope and the Indian Ocean. As is not uncommon in the history of humankind the pastoral Tutsi tended to dominate the Hutu peasant. This is where the class dimensions are clearest, as the modest Hutu were traditionally ruled by the wealthier Tutsi aristocracy.


The problem is when one makes recourse to Platonic thinking when population thinking would be more useful. There are certain average differences between the Tutsi and Hutu, but there is a great deal of overlap. Not all Tutsi were wealthy pastoralists, and not all Hutu were peasant vassals. There was a caste system of a sort, but it was semi-permeable, and the identity of an individual as Hutu or Tutsi was partly conditional on social, economic, and personal circumstances. The key word here is partly. Additionally, the semi-permeability of identity does not imply that these categories emerged from a previously aggregate population.

An example of what I’m talking about would be the blood nobility of France in the late 18th century. The vast majority of the hereditary aristocracy derived from those who had been promoted in previous centuries from the gentry class of commoners. A division between the aristocracy and the commons in France in the 18th century, which loomed so large, and later gave raise to racialist theories, was almost totally a function relatively recent social forces. At this point some of you may point to the international connections of the French aristocracy. For example, the nobility of Normandy not only had Norse ancestors, but also centuries long connections with England. This is wrongheaded. Because aristocratic lineages tend to keep relatively punctilious records it is clear that turnover was so high that over the centuries ethnically based aristocracies melted into the population, and the nobility of the future itself was more than likely not either of novel foreign origin, or uplifted from the local stock (or, as in the case of Hungary, the elites imposed their identity upon the masses, who later seem to have replaced them if ancient DNA surveys of cemeteries are any clue).

The application of this sort of framework then seems natural to the Tutsi-Hutu dichotomy. Because this topic is of great interest there’s an independent entry on this question in Wikipedia, Origins of Tutsi and Hutu:

The colonial scholars who found complex societies in sub-Saharan Africa developed the Hamitic hypothesis, namely that “black Europeans” had migrated into the African interior, conquering the primitive peoples they found there and introducing civilization. The Hamitic hypothesis continues to echo into the current day, both inside and outside of academic circles. As scholars developed a migration hypothesis for the origin of the Tutsi that rejected the Hamitic thesis, the notion that the Tutsi were civilizing alien conquerors was also put in question.

One school of thought noted that the influx of pastoralists around the fifteenth century may have taken place over an extended period of time and been peaceful, rather than sudden and violent. The key distinction made was that migration was not the same as conquest. Other scholars delinked the arrival of Tutsi from the development of pastoralism and the beginning of the period of statebuilding. It appears clear that pastoralism was practiced in Rwanda prior to the fifteenth century immigration, while the dates of state formation and pastoralist influx do not entirely match. This argument thus attempts to play down the importance of the pastoralist migrations.

Still other studies point out that cultural transmission can occur without actual human migration. This raises the question of how much of the changes around the fifteenth and sixteenth centuries was the result of an influx of people as opposed to the existing population being exposed to new ideas. Studies that approach the subject of racial purity are among the most controversial. These studies point out that the pastoralist migrants and pre-migration Rwandans lived side by side for centuries and practiced extensive intermarriage. The notion that current Rwandans can claim exclusively Tutsi or Hutu bloodlines is thus questioned.

The idea that people have “pure” Tutsi or Hutu “bloodlines” is so easily refuted that we can dismiss it and move on. Even species can hybridize, so the notion that populations which were spatially coexistent for centuries would be able to maintain pure distinctiveness seems ludicrous. But this idea was proposed by Europeans in the 19th and early 20th centuries, influenced by the racialist paradigms ascendant at the time, whereby the Tutsis were conceived as an intrusive Eurasian population which imposed its will upon the primitive Bantu Hutu. Interestingly these same concepts were resurrected by Hutu demagogues after independence, though the valence of division was altered, insofar as the Tutsi were now no longer vectors of civilization, but alien interlopers who brought contagion.

Most of these models are ridiculous on the face of it. But the converse extreme position is that the Tutsi-Hutu division was purely a cultural revolution, and that the Tutsi are as native as the Hutu in terms of the time-depth of their biological ancestry in the region of Rwanda-Burundi. A common observation here is that one couldn’t tell a Tutsi from a Hutu. This sentiment was put into the mouth of Joaquin Phoenix’s character in Hotel Rwanda. But this is obviously wrong. Some Hutu become Tutsi, and some Tutsi become Hutu, and some people have mixed ancestry but undivided identity, but the reality remains that on average the Hutu and Tutsi do look different. This was obvious in Hotel Rwanda itself, the Hutu protagonist’s Tutsi wife was played by a half-white actress. The preconception is that Tutsis are taller and have narrower features. Paul Kagame, the de facto ruler of Rwanda since 1994, and an ethnic Tutsi, is a perfect exemplar of the prototype Tutsi. He is tall, slim, and has relatively narrow features.

No matter the line promoted by the government of Rwanda after the genocide the people of the region are quite aware of Tutsi distinctiveness, or at least the ideal distinctiveness of the Tutsi. In Dancing in the Glory of Monsters the author observes that illiterate peasants in the eastern Congo will routinely express skepticism of an individual by bringing up the French form of the word morphology. This scientific term, which describes the exterior and structural phenotype of an individual illustrates the depth of a racial understanding of the difference between the Tutsis and other populations of this region.

So what’s the truth here? I can now contribute a little to the elucidation of this question, because I have run the genotype of an individual who is 3/4 Rwandan Tutsi and 1/4 Rwandan Hutu. An N = 1 is not much, but it is far better than 0. There are some genetic studies of these populations, but they don’t use hundreds of thousands of SNPs. I did. More specifically, a little over 400,000 SNPs.

I first ran this individual in a trial set of populations using both ADMIXTURE and Eigensoft. The former partitions the ancestry of an individual into K components, weighted by the contribution of each component. These are not to be taken literally. In this case focus rather on the relatively comparison across populations, rather than the absolute values of each individual. Eigensoft generates PCA plots, which extract out the largest independent dimensions of genetic variation in the population. These dimensions are ordered from larger (1st component) to smallest (nth component).

Eventually I discarded most of the non-African populations, as well as the Mozabites. My main focus was on East Africa. I have no Hutu samples, but I do have Luhya from the HapMap. They are a Bantu group from western Kenya, and so presumably relatively good proxies for the Hutu. In the following analyses you should substitute “Hutu” implicitly when you see “Luhya.” The other groups are rather straightforward. I included some Yoruba as a West African outgroup, but left them out of the ADMIXTURE plot because at higher K’s internal structure began to show up. This didn’t change the overall results, but they don’t inform for the Yoruba. The Sandawe are a Tanzanian group which speaks a language with possible affinities to the Khoe.

k7_all
pca_1_2
pca_1_3
pca_1_4
pca_1_7

The figure to the left shows all the individuals in the ADMIXTURE run labeled by population (except the Yoruba). Near the bottom I’ve placed a red marker to point to the Tutsi. Both the PCA and the ADMIXTURE indicate that this Tutsi individual has a strong resemblance to the results for the Masai. Unsurprisingly this individual is shifted somewhat toward the Luhya in the PCA, further confirmation of their Hutu ancestry. We can probably reject an Afro-Asiatic ancestry for the Tutsi, as is claimed by some. This individual consistently shows much closer affinity to the Nilotic Masai than to the Semitic or Cushitic samples from the Horn of Africa. Also, notice the profile of the Bantu of Kenya. These are likely good proxies for the ur-Hutu. The Tutsi individual is far outside of the range of this population.

What does this mean? I think the title says it all: the Tutsi were in all likelihood once a Nilotic speaking population, who switched to the language of the Bantus amongst whom they settled, and from whom they extracted rents. The relationship of the Tutsi and Hutu is not exceptional, and does not require European colonial intervention or meddling. It is a representative of a range of relationships whereby mobile pastoral populations dominate sedentary farmers because of their superior martial prowess (farmers are “sitting ducks”). Quite often this division has some ethnic connotation, such as the Scythian dominion over various sedentary populations in the Ukraine ~2,000 years ago, or Turkic hegemony in late medieval and early modern Russia. Neither the Scythians nor the Turks emerged from the sedentary substrate. Rather, they were intrusive to the region. Despite the interaction and intermarriage between these sorts of populations they generally remain aware of their disparate origins, and conscious of it. The fact that the Tutsis and Hutus do should not surprise that much in this context.

When it comes to some scientific questions, such as the genetic basis of intelligence, the science isn’t quite there to resolve the issues to the satisfaction of all in the room. I believe it will, but it will take time. But in the cases of ethnic identity and its relationship to biology we have the technology. The Tutsis and Hutus in all likelihood derive from two distinctive biological groups, who have not become divided, but rather have amalgamated somewhat over time (culturally and biology). That’s a lot to derive from one 3/4 Tutsi sample, but we have more to  go on than just this sample. There has been long a suspicion about the Tutsi’s non-Bantu origins due to phenotype, oral history, and lifestyle. I’m basically confirming what is evident to anyone who has eyes.

The reason that the Rwandan authorities don’t emphasize the differences between the Tutsis and Hutus (despite the current Tutsi domination of the government) is because of the history of ethnic violence and genocide in the region. But I do not believe that the genetic differences that are clear here are sufficient or necessary for genocide. This is famously illustrated by the Yugoslav conflicts of the 1990s, where very biologically similar groups engaged in wars based on their putative differences. Within Africa itself there is no shortage of genocide between groups which are much closer biologically than the Tutsi and the Hutu (e.g., the havoc wrought upon the Bantu Matabele in the early 1980s by the Bantu Shona dominated movement led by Robert Mugabe). It is not the truth we have to fear, but the mythologies which humans distort from the fragments of the truth in furtherance of their own perverse aims.

Note: thanks to everyone who spread the word about my quest for a Tutsi genome. I think we just did something really cool here.

  • http://mygenomix.wordpress.com Moreno

    Great work! If you had more samples you could write a paper about this.
    So pastoralists overcome peasants who overcome hunter-gatherers? Is this the ultimate message from history? (I’ve just finished “Guns, germs and steel”)

  • Muzungu

    Living in Rwanda I’ve pondered over this debate a lot, and this is definitely interesting work but it doesn’t really answer any of the arguments against distinct ethnic groups, based on examination of culture. For example:
    1. Why do the Twa people who are considered the original inhabitants of Rwanda, and who generally keep to themselves share the same language of Kinyarwanda as the Hutu and Tutsi?
    2. Why are Tutsi physically similar to the Kikuyu in Kenya, who speak a Bantu language which is relatively close to Kinyarwanda?
    Any ideas?

  • unknown

    According to Tishkoff et al.

    The Maasai were collectively around…

    ~50% Cushitic
    ~25% Nilo-Saharan
    ~25% Niger-Kordofanian

    The Luhya were…

    ~78% Niger-Kordofanian
    ~15% Nilo-Saharan
    ~7% Cushitic

    The Kikuya from Tishoff et al. and the Hema samples from elsewhere were around…

    ~40% Cushitic
    ~45% Niger-Kordofanian
    ~15% Nilo-Saharan

    The Tutsi I would imagine would most resemble the Kikuya and Hema, other SE African Bantu speaking populations with Cushitic/Nilotic admixture.

  • unknown

    ^ More so than the Maasai who are Nilo-Saharan speakers that absorbed Cushitic/Niger-Kordofanian admixture.

  • Ukuri

    Close enough! I am Rwandese and from all I know, this is as close as it gets. No bias, pure science and history combined in a fashion closest to what nobody wants to really say.

    @Moreno: Basically that’s what he;s saying. Only that all the three groups somehow overlapped and over time came to be more of social castes than biologically meaningful groups.

  • Eze

    We can probably reject an Afro-Asiatic ancestry for the Tutsi, as is claimed by some. This individual consistently shows much closer affinity to the Nilotic Masai than to the Semitic or Cushitic samples from the Horn of Africa.

    That’s an interesting possibility, but this admixture run didn’t split the non-hunter-gatherer Africans that well. In one of your previous analyses on East Africa you managed to get a pretty accurate ‘Afro-Asiatic/Cushitic’ and ‘Nilotic’ cluster. Is it possible that you could run this Tutsi sample using the same admixture settings as in the ‘Flavors of Afro-Asiatic’ blog post to see if he carries a significant Nilotic component or is mainly Bantu & Cushitic derived?

  • Dunia

    Thanks for this scientifically documented details regarding the Hutu and Tutsi. Is it possible to indentify the DNA of Hutu and the DNA of Tutsi as well ? and if this is possible , it can prove who Hutu or Tutsi is , and therefore people can know exactly how many Hutus or Tutsis were killed in the Rwanda genocides(exact figure)

  • Slater

    Having been to the region myself, I can say that despite the stereotypes, the vast majority of people there are unidentifiable as one group or the other. Unless you ask them, you would not be able to tell. Until the colonial powers emphasized the divisions, they really were only economically-based, though not entirely as you pointed out. Aside from the different migratory histories the two groups really assimilated in the region. I would even go so far as to call them homogenous (at least before the colonial powers intervened). It was only after the colonial powers elevated the Tutsi’s in society and mandated identification that specified the ethnicity, did ethnicity become a factor of division in the Great Lakes. I’d recommend reading “Strength in What Remains” by Tracy Kidder. I think she offers a balanced perspective on this.

    As for the science of this, I’d be interested to hear where you got your data from. It seems to me that despite your valiant attempts to retain a scientific standard, I think you deviate some with assumption and expectations that affect your simulations.

    That being said, this is certainly an interesting topic of both discussion and research. I’d be interested in hearing more about it if you do further work.

  • unknown

    ***We can probably reject an Afro-Asiatic ancestry for the Tutsi, as is claimed by some. This individual consistently shows much closer affinity to the Nilotic Masai than to the Semitic or Cushitic samples from the Horn of Africa.***

    The Maasai are a Nilotic speaking population, but they’re not necessarily biologically “Nilotic” as is the case with the Dinka and other populations from Southern Sudan. The Maasai are a mixed group, as are Rwandans/Burudians, and therefore explaining why the two populations cluster together… in between West Africans and Semitic/Cushitic speaking populations from the Horn of Africa. It would have had been naive for us to assume that the Tutsi would cluster in the vicinity of the Oromo or Somali, nevertheless the Amhara and Tigray, given the fact that the Tutsi’s Afrasan speaking ancestors would have logically exchanged gene-flow with populations in SE Africa… even before actually reaching the Great Lakes region.

    In my opinion, the significant Cushitic component found among Rwandans expanded into the region by way of Tanzania, from a population similar to that of the Iraqw. This ancestral SE African Cushitic population then likely originated and migrated from the vicinity of southern Ethiopia; this ancestral Horn of African population was likely ancestral to populations similar to the Borana, Gabre, and other Oromo peoples, more so than the eastern Somali and the northern Agaw (and their pseudo-Semitic cousins, the Amhara and Tigray). Further research on SE African genetics will likely confirm the predominant “Oromo-like” affiliation of the Cushitic admixture found among Bantu, Nilo-Saharan, Afrasan, and Sandawe SE Africans. The other Cushitic affiliation in SE Africa is probably the more “eastern orientated” component found among the Somali; but such ancestry is probably limited to the likes of the Rendille, El Molo, and the Somali themselves.

    The Nilotic admixture in Rwanda/Burundi is either “indigenous” to the Great Lakes region and/or came by way of Southern Sudan via Uganda, in a separate wave of gene-flow into the region… I highly doubt that the population that introduced Cushitic admixture in the region also introduced the aforementioned Nilotic affiliation. Uganada, geographically, is roughly split between Niger-Kordofanian and Nilotic speaking populations. And many of the Great Lakes communities in Kenya are also Nilotic speaking, including for example the Kalenjin. These populations are not recent migrants, as are the Maa and Turkana speaking communities. I currently favor the former scenerio, in which Nilotic speakers in the Great Lakes region where eventually absorbed by incoming Bantu and Cushitic speaking populations. Both the Luhya and “Bantu Kenyans” from Tishkoff et al 2009 posses “Nilo-Saharan” admixture at ~15-20%.

    ^ Tanzanian Bantu groups lack the Nilotic component, while Great Lakes and further eastward Kenyan samples do… probably due to different reasons, indigenous and intrusive.

    ***Unsurprisingly this individual is shifted somewhat toward the Luhya in the PCA, further confirmation of their Hutu ancestry.***

    I don’t think that’s the most logical explanation. The Tutsi are a Bantu speaking population, while the Maasai are a Nilo-Saharan speaking population… while both possess significant Cushitic ancestry, they possess varying levels of Bantu and Nilo-Saharan admixture. Tutsi’s being Bantu are going to possess more Niger-Kordofanian ancestry, while the opposite is true with the Maasai. The fact that his grandfather is Hutu is likely insignificant in this context, given that even the most Cushitic admixed Tutsi likely has a stronger pull to the Luhya or Central African than they do with Southern Sudan. And I’m willing to bet that a significant portion of the Hutu population cluster closer to this Tutsi sample than the Luhya do… given the fact that many Hutus have Tutsi ancestry, in contrast to vise-versa; Hutu men-Tutsi women unions were common in Rwanda-Burundi up until recently, and in these cases the “mixed” children of these unions would be classified as “Hutu” no matter their Tutsi ancestry. Class identity is transmitted via the father.

    The aforementioned many explain why the Maasai are slightly closer to the Horn of Africa in comparison to the Tutsi, given that the Nilo-Saharan component is naturally closer to the Cushitic component in contrast to the Niger-Kordofanian component.

    side note: this particular Hutu grandparent while being “Hutu” looks remarkably “Nilotic” and could easily pass in the Sudan.

  • carpetanuiq

    “It is not the truth we have to fear, but the mythologies which humans distort from the fragments of the truth in furtherance of their own perverse aims”

    Good research and true conclusion. Mythology and history rewriting is the first signal of political identity change, since past facts must be consistent with present identities. This rewriting is not arbitrary but natural: political identity change follows underlying society change.

    An example, besides hutus and tutsis, is the Duchy of Brabant. During all the Ancient Régime agricultural society, language diferences existed but did not generate political identities. Flemings and waloons from the duchy would fight together against flemings from the County of Flanders, or waloons from Hainaut. In today industrial / post industrial Belgium, the political identity divide is linguistic. And (I suppose) the rewriting is at place.

    Regarding nobility pls let me clarify one point. French and european nobilities had a scale of values that measured four parameters: origin and antiquity (la “race”, “l´ancieneté”, “uradel” in german), hereditary property (le “patrimoine”) , pedigree / marriage (les “alliances”) and finally the meritocratic parameter, actions made during life (les “illustrations”, if possible military). The four had to be balanced in a lineage. The first was the more important because it was time asymmetric and caused an important divide in noble lineages. Balanced “uradels”, considered themselves an elite within nobility and were very conscient of the value of this: they still intermarried until recently (first half of XX century). Also unbalanced unpoverished “uradels” exchanging it for patrimoine with unbalanced new rich lineages.
    .

  • Ian

    @Moreno: So pastoralists overcome peasants who overcome hunter-gatherers? Is this the ultimate message from history?

    Not entirely. Pastoralists overcome peasants politically, sometimes culturally, but rarely demographically. Demographically, I think the peasants almost always win.

  • Bronze Age Pervert

    Is this the ultimate message from history?

    would you be a farmer, clearing out the land, making its fruit increase, your calloused hand raising up the sweet corn out of the black earth, living with woman and children in an orderly household…or would you be a pastoralist, in your youth you would don the wolfskin and haunt the mountain crags and with your companions raid the lush valleys, stealing many fine cattle and women and barrels of grain and oil, with the smell of blood always in your nose, like a pack after a hunt gathers around a black lake and their red tongues lap at the waters

  • Omar

    2. Why are Tutsi physically similar to the Kikuyu in Kenya, who speak a Bantu language which is relatively close to Kinyarwanda?

    I’m not sure about this. The physical resemblance between Kikuyus and Tutsis seems very small to me. I have lived in both countries for years, but more so in Kenya than Rwanda. First of all, Kikuyus, on average, are not slim and tall (I understand that not all Tutsi are like Kagame). They are probably at or below the average Kenyan height. It’s true that they (not all them but on average – and especially their women) do have prominent foreheads, similar to the one on Kagame. They also have a fairer complexion than Luos, Luhyas, Kalenjins, Masais and others. However, there are other ethnic groups in Kenya with closer physical resemblance to Tutsis than Kikuyus, especially morphologie-wise: Kalenjin and Masai

  • Kinyanj

    I am a Kikuyu. I am just speculating based on stories I heard from older Kikuyus growing up in Kenya. Old Kikuyus speak of a place called Hakum (axum). Axum is a location somewhere in Ethiopia. Kikuyus believe to have migrated down from there prior settling in Kenya. If Tutsi Also Have a Similar story which im not sure if they do, Then the only thing i can say is that at some point both Kikuyu and Tutsis whether they were originally Bantu or Cushite, They intermarried alot between Bantu and Cushites which would bring about the Big forehead and fairer skin. Just trying to connect the dots. Here is some other info that can support my theory http://africanpress.wordpress.com/2008/02/15/kikuyus-tutsi-merus-kambas-and-embus-ended-up-in-their-current-locations-due-to-migration/

  • Muzungu

    @Slater “I can say that despite the stereotypes, the vast majority of people there are unidentifiable as one group or the other. Unless you ask them, you would not be able to tell”

    I’m assuming you’re not from the region and would disagree with this. And to say that the groups were “homogenous” prior to colonialization is pretty naive. What about socially homogenous? The RPF is pushing this version of history on everyone because they know that minority rule never lasts long. One can make a philosophical argument for why it’s better for Rwandans to believe that ethnicity was a colonial invention (I’m open to that), but it’s probably not reality.

  • http://bluetenlese.wordpress.com M. Möhling

    ot:
    > the havoc wrought upon the Bantu Matabele in
    > the early 1980s by the Bantu Shona dominated movement led by Robert Mugabe
    can you recommend readings on the subject?

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    I’m assuming you’re not from the region and would disagree with this.

    don’t you know, all black people look the same? :-)

    can you recommend readings on the subject?

    i don’t remember anymore where i read this. the falling out between the shona and matabele factions is well known so i’m sure you could find stuff on google books.

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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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