Fertility of Abnormal Hemoglobin Carriers in Porto Alegre, Brazil

Abstract

No significant differences were observed on the average number of pregnancies and livebirths, as well as on the frequencies of spontaneous abortions, stillbirths, premature children and those dying before the age of reproduction when the reproductive performances of 123 couples having at least one abnormal hemoglobin carrier were compared with the same number of appropriately chosen controls. The number of sibs of these carriers and of those with normal hemoglobin only did not differ significantly either. These and viability data reported elsewhere indicate essentially similar fitnesses for the individuals compared, who live in the nonmalarious environment of Porto Alegre. The fate of the Hb^s and Hb^c genes seems to be their gradual disappearance from this and other populations of the New World.

Hemoglobin variations on a small bahamian island

“…Malaria has not acted as a natural selection pressure as it has in some other New World groups (e.g., Firschein, 1961;Ferrell et al, 1978;Salzano et al, 1973). Certain features of Bimini's historical demography indicate that population migration from Africa and subsequent genetic drift have influenced the distribution of the observed gene frequencies.…”

“…The inherited hemoglobin variations S, C, and F are found at appreciably higher levels on Bimini than would be expected by recurrent mutation, and it is thus very likely that the polymorphisms are maintained by one or more evolutionary processes. Malaria has not acted as a natural selection pressure as it has in some other New World groups (e.g., Firschein, 1961;Ferrell et al, 1978;Salzano et al, 1973). Certain features of Bimini's historical demography indicate that population migration from Africa and subsequent genetic drift have influenced the distribution of the observed gene frequencies.…”