Sickle-cell anaemia is an evolutionary defence against what disease?

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Sickle-cell anaemia is a genetic blood disorder that primarily affects people of African descent. It is caused by a mutation in the gene that provides instructions for making haemoglobin, a protein in red blood cells that carries oxygen throughout the body. This mutation causes the blood cells to become sickle-shaped and break down more easily, leading to a shortage of healthy red blood cells and causing symptoms such as fatigue, pain, and organ damage. However, research has shown that individuals with the sickle-cell trait, who carry only one copy of the sickle-cell mutation, are more resistant to malaria, a life-threatening disease caused by a parasite that is transmitted through the bite of infected mosquitoes. The sickle-shaped red blood cells are less hospitable to the malaria parasite than normal red blood cells, making it harder for the parasite to multiply and causing it to die off more quickly. Therefore, sickle-cell anaemia may have evolved as a defence against malaria, providing a survival advantage for individuals who carry the sickle-cell trait in regions where malaria is endemic.

Sickle-Cell Anaemia Is an Evolutionary Defence Against What Disease