Mixed Race Studies

Y-STR diversity and ethnic admixture in White and Mulatto Brazilian population samples

Genetics and Molecular Biology (Former title: Brazilian Journal of Genetics)
Volume 29, Number 4 (São Paulo  2006)
pages 605-607
DOI: 10.1590/S1415-47572006000400004
ISSN 1415-4757

Luzitano Brandão Ferreira
Departamento de Genética, Faculdade de Medicina de Ribeirão Preto
Universidade de São Paulo, Ribeirão Preto, SP, Brazil

Celso Teixeira Mendes-Junior
Departamento de Genética, Faculdade de Medicina de Ribeirão Preto
Universidade de São Paulo, Ribeirão Preto, SP, Brazil

Cláudia Emília Vieira Wiezel
Departamento de Genética, Faculdade de Medicina de Ribeirão Preto
Universidade de São Paulo, Ribeirão Preto, SP, Brazil

Marcelo Rizzatti Luizon
Departamento de Genética, Faculdade de Medicina de Ribeirão Preto
Universidade de São Paulo, Ribeirão Preto, SP, Brazil

Aguinaldo Luiz Simões
Departamento de Genética, Faculdade de Medicina de Ribeirão Preto
Universidade de São Paulo, Ribeirão Preto, SP, Brazil

We investigated 50 Mulatto and 120 White Brazilians for the Y-chromosome short tandem repeat (Y-STR) markers (DYS19, DYS390, DYS391, DYS392 and DYS393) and found 79 different haplotypes in the White and 35 in the Mulatto sample. Admixture estimates based on allele frequencies showed that the admixture of the white sample was 89% European, 6% African and 5% Amerindian while the Mulatto sample was 93% European and 7% African. Results were consistent with historical records of the directional mating between European males and Amerindian or African females.

The Brazilian population is a result of interethnic crosses of Europeans, Africans and Amerindians, and is one of the most heterogeneous populations in the world. When the first European colonizers arrived (1500 AD), 1-5 million Amerindians already lived in the region that now is known as Brazil (Salzano and Callegari-Jacques, 1988). Before 1820, European colonization was almost exclusively composed of Portuguese while between 1820 and 1975 the great majority of immigrants were from Portugal and Italy, followed by a small number by people from Spain, Germany, Syria and Japan (Carvalho-Silva et al., 2001). Between the 16th and 19th centuries approximately 3.5 million Africans were brought as slaves to Brazil, coming mainly from West, West-Central and Southeast Africa (Curtin, 1969). The colonization of Brazil involved mostly European men, many of whom produced children with Amerindian and African females.

Although the classification of races is wrong from genetic standpoint (Templeton, 1998), Brazilians are classified for census purposes based on color. According to the last Brazilian government census of the 170 million Brazilians, 84 million were males, of which 52% were White, 39% were Brown, 6% were Black and 3% were classified in other categories (IBGE, 2000). Mulatto is the term commonly used in Brazil to designate the offspring result from the union of White and Black people. We used five Y-chromosome short tandem repeat (Y-STR) markers, recognized as good markers for population studies, to investigate genetic polymorphism and ethnic admixture in White and Mulatto Brazilian population samples.

We investigated 170 healthy, unrelated, individuals seeking paternity investigation at the Ribeirão Preto University Hospital, in the city of Ribeirão Preto, São Paulo state, Southeastern Brazil. The race of the individuals in the sample was determined based on their biomedical records, 120 individuals being White and 50 Mulatto, from Ribeirão Preto and the surrounding towns…

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