2013 autosomal DNA study on Brazil

[Lurker]

I don't think 1300 samples for a whole country is enough..

If there are 500 towns in Brazil, each town must have at least 100..because Brazil people's genetics varies dramatically within each state let alone whole Brazil

Brazil whites or Pardos or Blacks are not homogeneous enough and they are not closely related within themselves.


For instance when they say 80% (assume) European for Whites in North-east, realistic value could be 75% or any value..
Since we are more into comparing regions (north east vs south ancestry), accuracy's necessity is more needed.


These are just my personal opinions. I could be wrong.

I think the sample number is OK. Studies in the United States using the whole population use something like 600 samples. This one used 664 Americans to see if self-identification in 4 categories (white, black, asian and hispanic) were consistent with their ancestry.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3051415/

The US population is less heterogeneous than Brazil's, but it's still very heterogeneous nowadays (considering the whole country and the amount of admixture in US Hispanics and African Americans). Interestingly, the study showed 19.4% of US whites in clusters other than white and 22.2% of Hispanic americans clustering in clusters other than Hispanic.

[RMuller]

Brazil is extremely misrepresented abroad.

I have posted many crowd pics here from all over Brazil... they're almost never shown on international media.

http://www.theapricity.com/forum/sho...rowd-pictures)

Before the internet i use to think the average Brazilian looked like the soccer team and the people of carnaval of Rio .

[curupira]

Yes, Brazil is very misrepresented. No one thinks of the US as being like their basketball team or their football team, and yet a continental sized country like Brazil is reduced to the demographics reality of a few major cities, like Salvador and Rio.

Before the internet i use to think the average Brazilian looked like the soccer team and the people of carnaval of Rio .

Anyway, the main difference from the 2011 study: the 2013 was based on random urban samples, the 2011 study was based on 'white', 'pardo' and 'black' samples according to their respective proportions. On this, the 2011 study may have had a better strategy. On the other hand, the 2013 studied focused on the urban population, which as they mentioned accounts for the vast majority of the Brazilian population.

[curupira]

bump

[Lucinho]

~75% of them were males with short life expectancies. They were not settled uniformly throughout the country, but almost only in the coastal area and mining regions. They did not have 'normal demographics', at least until slavery was abolished in 1888.

Brazil is very misrepresented, and this makes the study of its demographic/genetic history only more significant then.

Over 80% of Brazil's population in still concentrated in the coastal areas and mining regions...

[curupira]

Not really, look at the map more accurately. São Paulo, which has about 40 million, has a large population in its interior, and so does Southern Brazil.

A density map is different from a populational map. Northern and Central West Brazil have tens of millions of Brazilians (since they occupy very large areas a density map would make them look with lower population than they actually have). Large parts of Northeast Brazil, like Ceará, were not really really impacted by Africans, even if its population is more coastal.

This a map of Brazil with its states by population:

Pará, Maranhão and Ceará in Northern and Northeast Brazil are states with large populations (over 5 million). And so is Goiás, in Central West Brazil. Minas Gerais and Rio have large populations, but they are largely mixed states. Rio, in particular, has a very high largely euro population. On the other hand, São Paulo state has a population of 40 million, much larger than the population of Minas and Rio together, and São Paulo is remarkably less african than both (even if including Bahia). Then you have Rio Grande do Sul and Paraná, which also have large populations, where non african ancestry accounts for about 90% of the heritage of the population.

Over 80% of Brazil's population in still concentrated in the coastal areas and mining regions...

[Lucinho]

Not really, look at the map more accurately. São Paulo, which has about 40 million, has a large population in its interior, and so does Southern Brazil.

A density map is different from a populational map. Northern and Central West Brazil have tens of millions of Brazilians (since they occupy very large areas a density map would make them look with lower population than they actually have). Large parts of Northeast Brazil, like Ceará, were not really really impacted by Africans, even if its population is more coastal.

This a map of Brazil with its states by population:

Pará, Maranhão and Ceará in Northern and Northeast Brazil are states with large populations (over 5 million). And so is Goiás, in Central West Brazil. Minas Gerais and Rio have large populations, but they are largely mixed states. Rio, in particular, has a very high largely euro population. On the other hand, São Paulo state has a population of 40 million, much larger than the population of Minas and Rio together, and São Paulo is remarkably less african than both (even if including Bahia). Then you have Rio Grande do Sul and Paraná, which also have large populations, where non african ancestry accounts for about 90% of the heritage of the population.

lol I could do the same picking states with large Black populations.

Bahia, Minas, Rio, Pernambuco, Alagoas, Sergipe, Espírito Santo, São Paulo (yes, it does have many Blacks) account for 80%¨of the Brazilian population. Moreover, there are Blacks and mixed people with visible African features in all other areas of Brazil. According to this genetic study that u are posting everywhere African ancestry is stronger than Amerindian even in the central-west, Mato Grosso do Sul

http://www.plosone.org/article/fetch...esentation=PDF

Even in Mato Grosso do Sul the average person has 25% of African ancestry, the same as having a full-blooded African grandparent. This is a lot and DOES influence a person's phenotype

[curupira]

In all of the states you mentioned except for Bahia (which I'm unsure of) european ancestry is more important, and there is native american ancestry too.

lol I could do the same picking states with large Black populations.e

[Lucinho]

In all of the states you mentioned except for Bahia (which I'm unsure of) european ancestry is more important, and there is native american ancestry too.

lol nobody is denying that. But according to your beloved genetic study European ancestry is only 56% in the Northeast. When you mix Portuguese with Black and Amerindian you get a very dark type, based on the fact that the Portuguese are not blond and pale themselves

[curupira]

I'm not eurocentric, my friend. I'm just for the truth, ok? Northeast Brazil is misrepresented generally, when if fact it tends to be European/African/Native American like the rest, just in different proportions, depending on the individual and on the region.

lol nobody is denying that. But according to your beloved genetic study European ancestry is only 56% in the Northeast. When you mix Portuguese with Black and Amerindian you get a very dark type, based on the fact that the Portuguese are not blond and pale themselves