Inbreeding effect on morbidity: I. Three analyses (one with cousin and sib controls) of two surveys among Brazilian whites and Negroes.

Data from two surveys performed in Brazil and involving 5,719 persons have been subdivided into three subsamples (one with cousin and sib controls). The totals led to estimates of B (abnormal equivalents per gamete) around 0.5, of A (the damage in a noninbred population) around 0.01-0.02, and of B/A from 14 to 77. No statistically significant difference was found between whites and nonwhites (mulattoes and Negroes). Inbreeding seems to disclose a predominantly mutational load.