Final answer:
The genetic conditions hemoglobin S, hemoglobin C, hemoglobin E, and G6PD deficiency are adaptations providing resistance to malaria. These conditions offer selective advantages in malaria-endemic regions, aligning with the theory of natural selection. Carriers of these traits are more likely to survive and reproduce in areas where malaria is common, keeping these mutations in the gene pool.
Step-by-step explanation:
The genetic condition that is an adaptation to malaria disease is the presence of mutated hemoglobin variants such as hemoglobin S, hemoglobin C, and hemoglobin E, and a mutation in the glucose 6-phosphate dehydrogenase (G6PD) gene. Hemoglobin S is an abnormal hemoglobin variant found in sub-Saharan Africa, the Middle East, and India. Hemoglobin C is another variant found mainly in West and North Africa, while hemoglobin E is prevalent in South and Southeast Asia. These hemoglobin variants affect the shape and functioning of red blood cells and provide some resistance to malaria. Those with G6PD deficiency, which can lead to a rare anemia, are also less prone to malaria infection. Carriers of these genetic traits have a selective advantage in malaria-endemic regions, as these mutations can lead to a reduced risk of severe malaria infection.
This relationship aligns with Charles Darwin's theory of evolution by natural selection, suggesting that individuals with traits that provide a survival advantage in their environment are more likely to survive and reproduce. Thus, the mutations that confer resistance to malaria persist in populations where the disease is common, as these individuals have higher fitness in such environments.
Thalassemia is another type of inherited anemia caused by abnormal hemoglobin and a genetic adaptation to malaria, notably in the Mediterranean region, parts of Africa, and South and Southeast Asia. In addition, the sickle-cell allele, known for causing sickle-cell disease, has a high prevalence in areas affected by malaria. The presence of just one sickle-cell allele (heterozygotes, AS) provides resistance to malaria, which helps maintain the allele in the population.