Properdin factor B polymorphism in Black Americans.

Properdin factor B is a genetically-controlled polymorphism that can be demonstrated by agarose gel electrophoresis. The Bf gene frequencies were determined for 194 blacks from the south-eastern United States. The frequencies for Bf-F, Bf-S, Bf-F1, and Bf-S1 are 0.626, 0.034, and 0.013, respectively. The south-eastern blacks have similar Bf frequencies to the South African blacks; however, both these groups are different from blacks from Boston. The frequency differences between south-eastern blacks and Boston blacks may be due to racial admixture differences found in the two populations.