Which individuals have the greatest fitness in an area where malaria is common?

Question

Quizplus · Accepted Answer

Individuals heterozygous for the normal and sickle cell anemia alleles have the greatest fitness in an area where malaria is common because they have some sickle cell hemoglobin which makes it difficult for the malaria parasite to complete its life cycle, but not enough to cause sickle cell anemia. This provides protection against malaria while not having the negative side effects of full-blown sickle cell anemia. Individuals homozygous for the normal globin allele are susceptible to malaria while individuals homozygous for the sickle cell anemia allele are at risk of developing sickle cell anemia, which is a debilitating condition. Individuals of any genotype who become infected with malaria before the age of five are at high risk for severe illness or death.

Which Individuals Have the Greatest Fitness in an Area Where