ABSTRACT
The geographical distribution of haemoglobinopathies bears a striking resemblance to that of malaria, one of the most powerful selective factors affecting human populations. As first proposed by Haldane in 1948, and now supported by a substantial body of experimental and epidemiological evidence, this reflects the protection afforded to carriers against Plasmodium falciparum. Haemoglobinopathies thus represent an example of a balanced polymorphism in which increased reproductive fitness among heterozygotes outweighs the survival disadvantage of homozygotes.
