Latin American genetic studies [official archive]

[Brighton]

Interesting! I remember seeing this study where they said 80% of Costa Ricans were White.. I was like no fucking way.

[Brighton]

Well to be fair this study was taken in Porto Alegre (Southern Brazil, very White city), Medellin (Whitest city in Colombia) and Arica (Literally the most Native city in Chile. Arica is actually closer to Lima than to Santiago).

So yep, not a fan of this study.. they should've done it in Santiago, it would've been so much better.

Also, the Chilean sample are professional soldiers, i.e. working class people, whilst for the other countries they used people from Uni, i.e. middle and upper-middle class people

[curupira]

Figures were given for nation-wide study, which had found that the Brazilian population as a whole was 59% European, 30% African, and 11% Amerindian.

I did not see a 30% african average for Brazil. This is what they said in the study (a maximum african % in Northeast Brazil of 30%; since Northeast Brazil is the most african part of Brazil, it follows the average African contribution is lower that, and even when it comes to Northeast Brazil that was the maximum figure found).

More European influence is observed in the southeast and south (up to 89%), while the African contribution predominates in the northeast (maximum estimate 30%) and the Amerindian in the north (up to 19%).

page 6

Here is a table with results by region in Brazil (a 30% african average is not likely, judging from these studies):

[Brighton]

Also, in Chile "White" and "Black" means "relatively pale" and "quite tanned", hence why "White" Chileans in this study are so mixed –there could be a balanced Mestizo with relatively pale skin but very Amerindian features- and why Black Chileans are actually only 13% African –they probs said "Black" cos they're very dark skinned.

[curupira]

Well to be fair this study was taken in Porto Alegre (Southern Brazil, very White city), Medellin (Whitest city in Colombia) and Arica (Literally the most Native city in Chile. Arica is actually closer to Lima than to Santiago).

So yep, not a fan of this study.. they should've done it in Santiago, it would've been so much better.

Also, the Chilean sample are professional soldiers, i.e. working class people, whilst for the other countries they used people from Uni, i.e. middle and upper-middle class people

They included samples from the different parts of each country though (the birthplace of individuals are indicated by purple dots on the African ancestry map):
http://journals.plos.org/plosgenetic...l.pgen.1004572

Colombia:



Mexico and Peru:



Chile:



Brazil:



I'm not sure the averages were calculated based on an equal number of samples or the weight ot each region relative to the others though.

[Brighton]

I did not see a 30% african average for Brazil. This is what they said in the study (a maximum african % in Northeast Brazil of 30%; since Northeast Brazil is the most african part of Brazil, it follows the average African contribution is lower that, and even when it comes to Northeast Brazil that was the maximum figure found).

page 6

Here is a table with results by region in Brazil (a 30% african average is not likely, judging from these studies):

You've got one that says "General" in the other image though.

To be honest I've been to Sao Paulo and I don't really think people were 75-80% European on average, but rather less than that.. or perhaps the African influence is just very visible phenotypically.

[curupira]

You've got one that says "General" in the other image though.

Ok, that is Manta et al study 2013. It is about Rio de Janeiro only though.

Manta, F. S. N., R. Pereira, A. Caiafa, D. A. Silva, L. Gusmão, and E. F. Carvalho. 2013. Analysis of genetic ancestry in the admixed Brazilian population from Rio de Janeiro using 46 autosomal ancestry-informative indel markers. Ann. Hum. Biol. 40:94–98.

[Brighton]

They didn't weigh the results though, that's the problem.. Porto Alegre, Medellin and Arica are overrepresented (so are Mexico City and Lima, but at least they're the most populated cities in those countries).

And even if they had weighted them –which they did not- it wouldn't be a fair comparison anyway cos the Chilean sample are soldiers and the other samples are Uni Professors/Students.. and we all know class and ancestry are related in our countries –sadly-.

[Brighton]

It says "general" Ribeirão Preto, a city in São Paulos state, that is very clear!

Haha nope, the results for Ribeirão Preto are the "Euro-Brazilians"/"Afro-Brazilians" right below it

[curupira]

Haha nope, the results for Ribeirão Preto are the "Euro-Brazilians"/"Afro-Brazilians" right below it

Yep, I saw it. They referred to the Manta et al study (2013) though (reference number #21). As you can see from my previous post, that is about Rio de Janeiro only (by mistake they labelled it as "general"):

Manta, F. S. N., R. Pereira, A. Caiafa, D. A. Silva, L. Gusmão, and E. F. Carvalho. 2013. Analysis of genetic ancestry in the admixed Brazilian population from Rio de Janeiro using 46 autosomal ancestry-informative indel markers. Ann. Hum. Biol. 40:94–98.

http://informahealthcare.com/doi/abs...60.2012.742138



Just by looking at regions results one can see that cannot be the average for the whole of Brazil (judging by the studies they have listed):