Mixed Race Studies

Gene Flow from White into Negro Populations in Brazil

American Journal of Human Genetics
Volume 9, Number 4 (December 1957)
pages 299–309

P. H. Saldanha
Department of General Biology
University of Sao Paulo, Brazil

GLASS AND Li (1953) have introduced a statistical model that allows calculations to be made, not only of the intermixture between two base populations but also of the dynamic pattern of the gene flow from one population to another, during a known period of intermixture. The formula derived from Glass and Li is:

To use this formula it is necessary to know: a) the gene frequencies, q₀ and Q, of the base populations; b) the gene frequency, q_k, of the hybrid population; and c) the number of generations, k, of contact between the base populations. The average rates of gene flow (m) from one population to another varies according to the assumed value of k and to the amount of accumulated admixture in the hybrid population. Some limitations of this method have been stressed by Glass and Li.

It should be of interest to compare the process of hybridization between Negro and White populations in Brazil to that in the United States, since the social conditions in the two countries have been and still are different. This is a first attempt to do so.

THE BRAZIL NEGRO

An important problem, which is not yet completely settled, is the African origin of Brazilian Negroes. The comparative ethnography of the Brazilian Negro was worked out, in its fundamental aspects, by the pioneer work of Nina Rodrigues (1932) and the later work of Ramos (1951a). The data on the relations between African and Brazilian cultural groups of Negroes shown in Table I result from these studies…

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Race Mixture among Northeastern Brazilian Populations

American Anthropologist
Volume 64, Issue 4 (August 1962)
pages 751–759
DOI: 10.1525/aa.1962.64.4.02a00050

P. H. Saldanha
Laboratória de Genética Humana
Faculdade de Medicina da Universidade de São Paulo, Brazil

Northeastern Brazilian populations are extremely interesting for racial studies. These populations are derived from the intermixture of Negroes, Whites (Portuguese), and Indians and seem to be very stable ethnic groups of which representatives are promptly recognizable because of their unique physical appearances. The “Nordestino” populations inhabit a very hostile region, arid almost throughout the year. Because of the poor conditions there, they often emigrate to southern regions of the country. The emigration flow of “Nordestino” is fairly organized, and migrants stay some days at the State Hostelry in São Paulo before they are directed to job centers.

About one year ago an investigation of blood groups, simple genetical traits, physical measurements, and other anthropological characteristics of “Nordestino” immigrants was initiated by two laboratories in the State of São Paulo. A preliminary report of these investigations will be published elsewhere. The present paper is concerned with some general problems of race admixture.

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