Carriers of the sickle cell allele
A) often do not display symptoms until after they have passed the gene on to their children.
B) can be treated during infancy if placed on a diet that is low in phenylalanine.
C) are more resistant to malaria than are individuals with two alleles for normal red blood cells.
D) develop sickle-shaped red blood cells that cause degeneration of the nervous systems.

Question

Quizplus · Accepted Answer

Carriers of the sickle cell allele have a heterozygous genotype, meaning they have one normal allele and one sickle cell allele. This genetic makeup provides a selective advantage in malaria-endemic regions because these carriers are less susceptible to severe forms of malaria. This phenomenon is a classic example of heterozyte advantage or balanced polymorphism, where the presence of the sickle cell allele in the population is maintained at a higher frequency because of its protective effect against malaria. Choices A, B, and D do not accurately describe the characteristics or implications of carrying the sickle cell allele.

Carriers of the Sickle Cell Allele