AbstractA total of 432 Whites and 654 Blacks were studied in relation to the index of pattern intensity and a smaller number (296 Whites; 496 Blacks) for total ridge count. There does not exist a clear gradient in either sex when the Blacks are subdivided into three phenotypic categories according to the amount of African ancestry they seem to possess. The standard deviations and coefficients of variation are strikingly similar in all groups studied. Racial differences in the averages of these two quantitative measures and in the asymmetry of total ridge count are small and nonsignificant. Fingerprints are very sensitive indicators of disturbances in the intrauterine development, and their asymmetry has a significant hereditary component. Since there is no increased or decreased asymmetry when we consider subgroups with various amounts of racial admixture, these and other results suggest that genetic adaptation in humans is a process involving mainly the whole species, and not narrow racial specializations.