Which of the following best describes the relation between sickle cell anemia and malaria? the two diseases do not co-occur the overabundance of hemoglobin caused by malaria counteracts sickle cell anemia the two diseases can co-occur but not in the same geographic region People who only have one allele for sickle cell anemia are poor hosts for malaria and therefore more likely to survive it The malaria parasite’s primary niche is inside people with sickle cell anemia.
The Correct Answer and Explanation is:
The correct answer is: People who only have one allele for sickle cell anemia are poor hosts for malaria and therefore more likely to survive it.
Explanation:
Sickle cell anemia is a genetic condition caused by a mutation in the hemoglobin gene. People who inherit two copies of the mutated gene (homozygous sickle cell) develop sickle cell disease, where their red blood cells take on a rigid, sickle-like shape, leading to blockages in blood flow, pain, and organ damage. People who inherit only one copy of the sickle cell gene (heterozygous) have what is called sickle cell trait. These individuals do not typically show symptoms of sickle cell disease, but they carry the gene and can pass it on to their offspring.
On the other hand, malaria is a parasitic disease caused by the Plasmodium parasite, which is transmitted to humans through the bites of infected mosquitoes. The parasite infects red blood cells, where it reproduces and leads to symptoms like fever, chills, and, in severe cases, organ failure or death.
Research has shown that individuals with sickle cell trait (having only one allele for sickle cell) are less likely to develop severe malaria. The presence of the sickle cell trait alters the shape of red blood cells in response to the malaria parasite, making it harder for the parasite to survive and reproduce inside the red blood cells. This provides some protection against malaria. As a result, people with sickle cell trait have a higher chance of surviving malaria compared to people with normal hemoglobin (who have no sickle cell alleles).
In regions where malaria is endemic, such as sub-Saharan Africa, this genetic trait has been naturally selected because it provides a survival advantage. This is why sickle cell trait is more common in populations living in malaria-prone areas. However, individuals with two copies of the sickle cell gene (homozygous) are at a higher risk of developing sickle cell anemia, and the presence of malaria does not provide them with protection.
