Which Individuals Have the Greatest Fitness in an Area Where

Question

Which individuals have the greatest fitness in an area where malaria is common?
A) individuals of any genotype who become infected with malaria before the age of five
B) individuals homozygous for the sickle cell anemia allele
C) individuals homozygous for the normal globin allele
D) individuals heterozygous for the normal and sickle cell anemia alleles

Accepted Answer

Individuals who are heterozygous for the normal and sickle cell anemia alleles possess an advantageous trait known as sickle cell trait. This trait provides a degree of immunity against malaria, as the parasite cannot easily infect and reproduce in the red blood cells of individuals with sickle cell trait. Therefore, in areas where malaria is common, individuals with sickle cell trait have greater fitness because they are more likely to survive and reproduce.