Question

Coupling is less prone to malaria?

• A. \( \text{Hb}^A / \text{Hb}^A \)
• B. \( \text{Hb}^A / \text{Hb}^S \)
• C. \( \text{Hb}^S / \text{Hb}^S \)
• D. None of the above

Hint:

The presence of the sickle-cell trait (heterozygous \( \text{Hb}^A / \text{Hb}^S \)) offers partial protection against malaria, which is why it is more common in regions where malaria is endemic.

Answer 1

The Correct Option is B

Individuals with the genotype \( \text{Hb}^A / \text{Hb}^S \), which means they carry one normal hemoglobin allele and one sickle-cell hemoglobin allele, are less prone to malaria. This is because the sickle-cell trait provides some protection against malaria, as the malaria parasite has more difficulty surviving in sickle-shaped red blood cells. This is why such individuals, though they may have sickle-cell disease (when both alleles are \( \text{Hb}^S \)), have a selective advantage in malaria-endemic areas. Option (B) represents this protective genetic coupling.