that the states with strongest African presence were Bahia and Minas Gerais, but that there is no region in Brazil where the black people have not penetrated. Many blacks fled to the hinterland of Brazil, including the Northern region, and met Amerindian and Mameluco populations. Many of these acculturated blacks were accepted in these communities and taught them the Portuguese language and the European culture. In these areas the blacks were "agents for transmitting European culture" to those isolated communities in Brazil. Many blacks mixed with the Amerindian and caboclo women. Geographic distribution of Black Brazilians , the Brazilian Metropolitan Area with the largest percentage of people reported as Black was Salvador, Bahia, with 1,869,550 Pardo people (53.8%) and 990,375 pretos (28.5%). The state of Bahia has also the largest percentage of "pardos" (62.9%) and pretos (15.7%). Other cities with significant Afro-Brazilian populations are Rio de Janeiro (where a 2013 study estimated that 31.1% of Rio de Janeiro's population is African-descended) and Belo Horizonte. Genetic studies A recent genetic study of African Brazilians made for BBC Brasil analysed the DNA of self-reported native Africans from São Paulo. The research analysed the mitochondrial DNA (mtDNA), that is present in all human beings and passed down with only minor mutations through the maternal line. The other is the Y chromosome, that is present only in males and passed down with only minor mutations through the paternal line. Both can show from what part of the world a matrilineal or patrilineal ancestor of a person came from, but one can have in mind that they are only a fraction of the human genome, and reading ancestry from Y chromosome and mtDNA only tells 1/23rd the story, since humans have 23 chromosome pairs in the cellular DNA. Analysing the Y chromosome, which comes from male ancestors through paternal line, it was concluded that half (50%) of Brazilian "negros" Y chromosomes come from Europe, 48% come from Africa and 1.6% come from Native Americans. Analysing their mitochondrial DNA, that comes from female ancestors though maternal line, 85% of them come from Africa, 12.5% come from Native Americans and 2.5% come from Europe. The high level of European ancestry in African Brazilians through paternal line exists because, for much of Brazil's History, there were more Caucasian males than Caucasian females. So inter-racial relationships between Caucasian males and native African or Native American females were widespread. Over