Who gave whom hemoglobin S: The use of restriction site haplotype variation for the interpretation of the evolution of the βS -globin gene.

The hypothesis that three separate mutations to the βS -globin gene have occurred in Africa in challenged. The distributions of the βS and other β-globin haplotypes and a simulation of the diffusion of the βS gene are presented and argued to be more in accord with the rapid diffusion of a single mutant that by recombination and gene conversion now occurs on several different haplotypes.