Navegando por Autor "SOUSA, Gabriella Pante de"

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Acesso aberto (Open Access)
Genetic relationships among native americans based on beta-globin gene cluster haplotype frequencies
(2003) RIBEIRO, Rita de Cassia Mousinho; SOUSA, Gabriella Pante de; SANTOS, Eduardo José Melo dos; GUERREIRO, João Farias
The distribution of b-globin gene haplotypes was studied in 209 Amerindians from eight tribes of the Brazilian Amazon: Asurini from Xingú, Awá-Guajá, Parakanã, Urubú-Kaapór, Zoé, Kayapó (Xikrin from the Bacajá village), Katuena, and Tiriyó. Nine different haplotypes were found, two of which (n. 11 and 13) had not been previously identified in Brazilian indigenous populations. Haplotype 2 (+ - - - -) was the most common in all groups studied, with frequencies varying from 70% to 100%, followed by haplotype 6 (- + + - +), with frequencies between 7% and 18%. The frequency distribution of the b-globin gene haplotypes in the eighteen Brazilian Amerindian populations studied to date is characterized by a reduced number of haplotypes (average of 3.5) and low levels of heterozygosity and intrapopulational differentiation, with a single clearly predominant haplotype in most tribes (haplotype 2). The Parakanã, Urubú-Kaapór, Tiriyó and Xavante tribes constitute exceptions, presenting at least four haplotypes with relatively high frequencies. The closest genetic relationships were observed between the Brazilian and the Colombian Amerindians (Wayuu, Kamsa and Inga), and, to a lesser extent, with the Huichol of Mexico. North-American Amerindians are more differentiated and clearly separated from all other tribes, except the Xavante, from Brazil, and the Mapuche, from Argentina. A restricted pool of ancestral haplotypes may explain the low diversity observed among most present-day Brazilian and Colombian Amerindian groups, while interethnic admixture could be the most important factor to explain the high number of haplotypes and high levels of diversity observed in some South-American and most North-American tribes.
Acesso aberto (Open Access)
Origin of the hemoglobin S gene in a northern Brazilian population: the combined effects of slave trade and internal migrations
(1998-12) SOUSA, Gabriella Pante de; RIBEIRO, Rita de Cassia Mousinho; SANTOS, Eduardo José Melo dos; ZAGO, Marco Antonio; GUERREIRO, João Farias
We analyzed DNA polymorphisms in the b-globin gene cluster of 30 sickle cell anemia patients from Belém, the capital city of the State of Pará, in order to investigate the origin of the bS mutation. Sixty-seven percent of the bS chromosomes were Bantu type, 30% were Benin type, and 3% were Senegal type. The origin of the bS mutation in this population, estimated on the basis of bS-linked haplotypes, contradicts the historical records of direct slave trade from Africa to the northern region of Brazil. Historical records indicate a lower percentage of people from Benin. These discrepancies are probably due to domestic slave trade and later internal migrations, mainly from northeastern to northern regions. Haplotype distribution in Belém did not differ significantly from that observed in other Brazilian regions, although historical records indicate that most slaves from Atlantic West Africa, where the Senegal haplotype is prevalent, were destined for the northern region, whereas the northeast (Bahia, Pernambuco and Maranhão) was heavily supplied with slaves from Central West Africa, where the Benin haplotype predominates.