Question

Which statement best explains the relationship between HbS allele frequency and malaria endemicity in Africa? When an area is malaria free, the HbS allele frequency is between 0 and 2.02. When an area is holoendemic, the HbS allele frequency is between 0.52 and 4.04. When an area is malaria free, the HbS allele frequency is between 12.64 and 18.18. When an area is holoendemic, the HbS allele frequency is between 0 and 0.51.

Answer 1

The answer is; When an area is holoendemic, the HbS allele frequency is between 0.52 and 4.04

Holoendemicity means that almost all individuals in a population are infected by a disease or pathogen (in this case Malaria) at one point in their lives. HbS allele is the sickle cell hemoglobin allele that provides immunity to malaria. Therefore, natural selection will favor the population with HbS allele in a Malaria holoendemic region. The HbS allele frequency in this population is expected to be high.

Answer 2

Answer;

When an area is holoendemic, the HbS allele frequency is between 0.52 and 4.04.

Explanation;

• HbS allele is the sickle cell hemoglobin allele that provides immunity to malaria. This is because people with the sickle cell allele have a selective advantage in areas where there is a high incidence of malaria.
• Therefore, natural selection will favor the population with HbS allele in a Malaria holoendemic (most individuals are infected) region. The HbS allele frequency in this population is expected to be high.
• After malaria is cured, the frequency of the HbS allele should decrease in regions with a lot of mosquitoes because having one copy of the HbS allele will no longer be advantageous in these regions.