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.If this population moves to an area without malaria,what will happen to the allele frequency of the A allele over time?

Question

Quizplus · Accepted Answer

In the absence of malaria, the selective advantage for carrying the S allele (resistance to malaria) disappears. Individuals with AA genotype do not face the increased risk of malaria and thus are not at a selective disadvantage. Over time, the frequency of the A allele will increase because the selective pressure that favored the AS genotype (malaria resistance) is no longer present.

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