Sickle cell anemia is a recessive disorder caused by a mutation
in the hemoglobin A gene. Persons with the disease have a variety
of serious health issues related to fragile and sickling red blood
cells including premature death, and infants sometimes die from
complications. In regions of central Africa where malaria is
endemic, the relative fitnesses for individuals that are homozygous
for the wild type hemoglobin allele (HbA), heterozygous
(HbAHbS), and homozygous for the sickle cell
allele (HbS) are 0.8,...