Final answer:
Sickle cell anemia is a genetic disorder caused by a mutation in the beta-globin gene. The mutation leads to the substitution of glutamate with valine in the beta chain of hemoglobin, resulting in the abnormal shape of red blood cells. This condition is prevalent in certain populations and can cause chronic anemia and other health complications.
Step-by-step explanation:
Sickle cell anemia is an autosomal recessive genetic disorder caused by a mutation in the beta-globin gene, resulting in the production of abnormal hemoglobin. In normal beta^A allele, the amino acid glutamate is present at position seven of the beta chain of hemoglobin. However, in sickle-cell beta^S allele, a single base pair change leads to the substitution of glutamate with valine at this position. This minor change in the amino acid sequence causes red blood cells to become crescent-shaped or sickle-shaped, affecting their ability to transport oxygen efficiently.
This genetic disorder is especially prevalent in populations from Africa, the Mediterranean, and parts of the Middle East. While carrying one copy of the sickle-cell allele (heterozygous) may confer some resistance to malaria, being homozygous for the sickle-cell allele (having two copies) leads to sickle cell anemia, a condition characterized by chronic anemia, pain crises, and potential organ damage.