ABSTRACT
BACKGROUND: The distribution of mitochondrial DNA (mtDNA) lineages in Brazil is heterogeneous due to different regional colonization dynamics. Northeastern Brazil, although being an important region in terms of human imigration and ethnic admixture, has little information regarding its population mtDNA composition. Here, we determine which mitochondrial lineages contributed to the formation of the Northeastern Brazilian population. Our sample consisted of 767 individuals distributed as follows i) 550 individuals from eight Northeastern states (Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, and Bahia) which were sequenced for mtDNA hypervariable segments I, II, and III; ii) 217 individuals from Alagoas and Pernambuco (previously published data). Data analysis was performed through sequence alignment and Haplogrep 2.0 haplogroup assignment tools. Furthermore, maternal ancestry distribution was contextualized and, when possible, related to historical events to better understand the biological interactions and population dynamics that occurred in this region since the beginning of colonization. RESULTS: Unexpectedly, Amerindian mitochondrial ancestry was the highest in the Northeastern region overall, followed by African, European and non-Amerindian Asian, unlike previous results for this region. Alagoas and Pernambuco states, however, showed a larger African mtDNA frequency. The Northeastern region showed an intraregional heterogeneous distribution regarding ancestral groups, in which states/mesoregions located to the north had a prevalent Amerindian ancestral frequency and those to the south had predominance of African ancestry. Moreover, results showed great diversity of European haplogroups and the presence of non-Amerindian Asian haplogroups. CONCLUSIONS: Our findings are in disagreement with previous investigations that suggest African mitochondrial ancestry is the most prevalent in the Brazilian Northeast. The predominance of Amerindian lineages exemplifies the importance of indigenous women in the formation of the population, despite intense African slave entry and conflicts with European settlers. The variable distribution of ancestral groups observed in the Northeast is in accordance with historical records showing the similarities with colonization dynamics occurred in the Amazon region and the Brazilian Southeast. Moreover, the variety of European haplogroups suggests multiple origins of founding groups, specially those found in Western European populations.
Subject(s)
DNA, Mitochondrial/genetics , American Indian or Alaska Native/genetics , Asian People/genetics , Black People/genetics , Brazil , Ethnicity/genetics , Female , Genetic Variation , Genetics, Population , Geography , Haplotypes/genetics , Humans , Phylogeny , White People/geneticsABSTRACT
Este trabalho propõe uma metodologia de classificação dos municípios brasileiros conforme a característica migratória, tendo como base as informações disponíveis no Censo Demográfico de 2000. Foram aplicadas análises multivariadas de redução e classificação de dados sobre um conjunto de variáveis selecionadas que descrevem a forma como os 5.507 municípios se articulam na rede migratória brasileira. Primeiramente, aplicou-se uma análise de componentes principais com a finalidade de reduzir o conjunto de variáveis originais em componentes não correlacionados entre si. Posteriormente, estes componentes foram empregados numa análise classificatória de cluster com o objetivo de estabelecer uma tipologia migratória das localidades em estudo. Os resultados mostraram que há importantes diferenciais na inserção dos municípios na rede migratória, na qual existe um grande número de lugares pouco conectados em contraste com um número pequeno de pontos que experimentam fortes conexões, e nos quais a população circula rapidamente. A classificação aponta para a existência de novas categorias de lugares, além das definições clássicas de atração e repulsão, como a rotatividade migratória.
The authors propose a method for classifying the 5507 municipalities in Brazil according to their characteristics of migration phenomena, as shown in the data now available from the 2000 National Brazilian Census. Multivariate classifications for data reduction and classification analysis were carried out on a set of selected variables that describe how the municipalities in the country are articulated with the overall Brazilian migration network. First a central component analysis was applied in order to reduce the set of original variables into a new set of uncorrelated components. Next these components were used in a classificatory cluster analysis with the purpose of establishing a migration typology for the locations being studied. The results showed that there are great differences among municipalities in their participation in the migration network. There are many municipalities with weak ties with the migration network and a few areas with strong ties, where the populations are very mobile. We have called these municipalities "rotative locations." This classification indicates the existence of new categories of territory beyond the classical definitions of attraction and repulsion, one example being these rotative areas.
Este trabajo propone una metodología de clasificación de los municipios brasileños según la característica migratoria, utilizando como base las informaciones disponibles en el Censo Demográfico de 2000. Se aplicaron análisis multivariantes de reducción y clasificación de datos sobre un conjunto de variables seleccionadas que describen la forma en la que los 5.507 municipios se articulan en la red migratoria brasileña. En primer lugar se aplicó un análisis de componentes principales con la finalidad de reducir el conjunto de variables originales en componentes no correlacionados entre sí. Posteriormente, estos componentes fueron utilizados en un análisis clasificatorio de cluster, con el objetivo de establecer una tipología migratoria de las localidades en estudio. Los resultados mostraron que hay importantes diferenciales en la inserción de los municipios en la red migratoria, en la que existe un gran número de lugares poco conectados en contraste con un número pequeño de puntos que experimentan fuertes conexiones, y en los cuales la población circula rápidamente. La clasificación señala la existencia de nuevas categorías de lugares, además de las definiciones clásicas de atracción y repulsión, como la rotación migratoria.