Amerindians of Brazil more numerous than you think

By Razib Khan | June 27, 2010 9:09 am





First, let’s see how well the markers allow for us to distinguish populations’ whose ancestry we’re pretty sure about.


No that bad. Observe the trailing off of Europeans and Amerindians along their axis of variation. From previous papers using SNP chips with hundreds of thousands of markers It seems that the HGDP Amerindian sample has non-trivial European ancestry, so it isn’t just a limitation of their marker set. This shouldn’t be that surprising in light of the history of Latin America, and the centuries of racial fluidity which occurred. Additionally, I assume that it would be more difficult to find markers which vary between Europeans and Amerindians than between these two groups and Africans (remember that Africans have more genetic diversity, and non-African populations can be thought of as simply one branch out of Africa).

The following chart shows the outcome from the markers across various regions of Brazil. I assume that the core American readership will be pretty ignorant of the regions, so this map will help. Southern Brazil is white. The rest of the country far less so. Gisele Bündchen and Alessandra Ambrosio are from Rio Grande do Sul in the far south. Adrianna Lima, pictured above, is from Bahia in the northeast. All of the panels are for whites (through self-identification) except for the last.


Despite the limitations of 40 markers I think the results here are probably pretty good. The South region has the whitest whites. This was an area with massive immigration, and fewer non-whites to start with. It is in the northeastern region that you see more Amerindian than black ancestry among the whites. From what I have seen in other papers the brown category in Brazil is more skewed toward European ancestry than panel F, so that’s why I assume that these are men who self-identify as black.

But for the purposes of my original question we need to assess ancestral contributions within these groups from Amerindians. The following table does just that.


The authors note a curious fact: there’s no statistically significant difference between the regions in terms of Amerindian ancestry for self-identified white Brazilians. This resembles the pattern we saw with Neandertal admixture, and I assume the explanation is the same: the integration of Amerindian ancestry occurred early in the history of the white Brazilian population and has now distributed throughout it via generations of intermarriage except for those with undiluted white immigrant heritage (e.g., Gisele, who comes from a German town). The figure for blacks from Sao Paulo is about the same as whites as well.

Let’s assume 10% Amerindian ancestry and 200 million Brazilians to make the math easier. Since it is about 10% in whites and blacks, I suspect it will be 10% in those who identify as mixed race as well. Where does that leave us? That would mean 20 million Brazilians of Amerindian ancestry! As you can see around 95% of the Amerindian genome in Brazil is found among those who do not self-identify as Amerindian.

For Americans (citizens of the USA) it is then interesting to wonder how much of the Native genome is found in whites, particularly old stock colonial descended whites, and how much in self-identified Native Americans. Looking at the genetic studies I believe that the Amerindian proportion is much lower among white Americans than 10%. Additionally, while 700,000 Brazilians identify as Amerindian, 2.4 million Americans do (though I believe that a much larger proportion of American Native Americans are of mixed ancestry than Brazilian Aboriginals). I think that the odds are that more ancestry which is pre-Columbian in the USA does reside within the white population than within the self-identified Native American tribes, but it may be a close thing. And of course there are Latino populations which need to be added into the equation, whose Amerindian ancestry is significant (in the case of Mexican Americans possibly preponderant), though it is of Mesoamerican origin.

But doing those sums is for another post.

Note: A preemptive apology to those who feel I’ve used the wrong term for any particular ethnic group. I have preferred the more Politically Correct (though less popular) term Native American in the context of the USA, but feel that Amerindian is technical or scholarly enough to evade charges of insensitivity.

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CATEGORIZED UNDER: Culture, Genetics, Genomics
  • Zachary Latif

    Interesting post and certainly raises the valid question that after a couple of generations “mixture” just gets blended into the population.

    Sort of leads the way for the high immigration Western societies; it may just be that in a couple of generations there will be evidence of mixture but ethnic cohesiveness won’t disintegrate.

    At any rate its always comforting to know when human populations didn’t die out but in one way or another persisted in a new permutation.

    It does raise the question whether “aesthetic preferences” had an effect on why some populations look differently to their “genetic mix” (Saudi Arabs with their ~30% Sub-Saharan African population and Jewish pops, which resemble their host population but are genetically interlinked).

  • Walter Sobchak


    Casino Gambling.

  • Steve Sailer

    About the same as Puerto Rico, right? I call it the Jennifer Lopez Effect.

  • Razib Khan

    yeah, i think about the same as puerto rico. at least the amerindian component. i think puerto ricans are a bit more black than white brazilians, but less black than brazilians as a whole.


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