The disease,sickle-cell anemia is common in malaria-infested areas because individuals that are heterozygous for the gene (AS)have enhanced resistance to malaria over normal individuals (AA).Individuals with severe sickle-cell anemia (SS)usually die before reproduction.Assume that a population under Hardy-Weinberg equilibrium has allele frequencies of A = 0.8 and S = 0.2.Assume that this population is then subject to the following selection forces:
AA: 15% die of malaria
AS: 5% die of malaria
SS: 100% die of severe sickle-cell anemia
What will be the frequency of the S allele after selection occurs?
A)0.0
B)0.04
C)0.15
D)0.18
E)0.3

Question

Quizplus · Accepted Answer

The frequency of the S allele after selection can be calculated by considering the survival rates of each genotype. The AA genotype has a survival rate of 85% (1 - 0.15), AS has a survival rate of 95% (1 - 0.05), and SS has a survival rate of 0% (1 - 1.00). Using these survival rates, the new allele frequencies can be calculated, resulting in an S allele frequency of approximately 0.18.

The Disease,sickle-Cell Anemia Is Common in Malaria-Infested Areas Because Individuals