In regions where malaria is present, it acts as a selective agent that favors the heterozygous phenotype, because people with sickle-cell trait produce more offspring than those with only normal hemoglobin, who may die of malaria.

Question

Quizplus · Accepted Answer

This is known as the heterozygote advantage or the malaria hypothesis, where individuals with one copy of the sickle-cell gene (heterozygous) have a survival advantage over those with two copies of the normal hemoglobin gene when malaria is present. This is because the sickle-cell trait changes the shape of red blood cells, which makes it harder for the malaria parasite to grow and multiply within them. Therefore, individuals with sickle-cell trait are more likely to survive and reproduce, passing on the trait to their offspring.

In Regions Where Malaria Is Present, It Acts as a Selective