Final answer:
Sickle cell anemia is caused by a single amino acid substitution where glutamic acid is replaced by valine at position six of the hemoglobin beta chain, which produces Hemoglobin S (HbS) and results in sickled red blood cells.
Step-by-step explanation:
Mutation in Hemoglobin Beta Chain Leading to Sickle Cell Anemia
The mutation in the beta chain of hemoglobin that results in the production of sickled red blood cells is known as sickle cell anemia. This mutation involves a single amino acid substitution at the sixth position in the beta chain of hemoglobin, where glutamic acid is replaced by valine. This alteration leads to the production of an abnormal type of hemoglobin referred to as Hemoglobin S (HbS). The presence of valine instead of glutamic acid creates a hydrophobic interaction which causes the red blood cells to assume a sickle or crescent shape, interfering with their ability to flow smoothly through blood vessels and deliver oxygen efficiently.
The sickle cell mutation is a point mutation, meaning it is a change in just one nucleotide of the DNA sequence that codes for the beta chain of hemoglobin. Considering that a hemoglobin molecule is made up of about 600 amino acids, encoded by three nucleotides each, this single base change has profound effects on the structure and function of hemoglobin. Sickle cell anemia disproportionately affects individuals of African descent and has been associated with some protective effects against malaria.