Heredity, race, and society.

  • Dunn, L. C. (Leslie Clarence), 1893-1974.
Date:
1947
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Heredity, race, and society. Source: Wellcome Collection.

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    mulattoes are very variable from light through inter mediate shades to black. Attempts to analyze the in heritance of skin color in Mendelian terms have not been very successful because white and Negro each include a number of different skin colors, and many other factors such as tanning and bleaching also affect skin color. But there is little doubt that at least two and probably several gene differences are concerned. In certain matings of mulattoes, about % 6 of the chil dren are white or close to it, as though two independent recessive factors had come together. In other matings the proportion of whites is lower and the number of gene differences probably higher. The number of gene differences between the races entering the cross is important because it determines how often individuals resembling the parent races will appear in the second and later generations after a cross. We have seen that, if Negroes and whites differ in only two genes for skin color, only one child in sixteen will have a black skin, and one in sixteen will have a white skin, in the offspring of mulatto marriages. With three genes showing no dominance, the chance of a white- skinned child would drop to one in sixty-four, with four genes to one in 256, with n genes to one in 4 n . In marriages of mulattoes with whites, the chances of birth of a child with a white skin are much higher: 1 in 4 with two genes, 1 in 8 with three, 1 in 2 n with n genes. One of the greatest absurdities of the so-called race problem in the United States is that anyone who ad mits having some African ancestry is classed as a Negro regardless of his or her appearance. A Negro is then, a member of a social and economic group rather than of a purely biological one. Some of the children born to such Negroes are indistinguishable from, and pass among, the whites in order to avoid anti-Negro discrimination. To estimate how frequently passing children will be born to parents of mixed European- African ancestry, we must take into account several characters. Most of the natives of Europe differ from a majority of the inhabitants of tropical Africa in skin