1. Amino Acid Sequence: The ss genotype has a serine (S) amino acid at position 6 of the beta-globin protein, while the AA genotype has an aspartic acid (D) at the same position.
2. Protein Structure: The difference in amino acid sequence between the ss and AA genotypes affects the structure of the beta-globin protein. The presence of serine (S) in the ss genotype results in a more flexible protein structure, while the presence of aspartic acid (D) in the AA genotype leads to a more rigid structure.
3. Hemoglobin Function: The structural differences between the beta-globin proteins in the ss and AA genotypes affect the function of hemoglobin. Hemoglobin in individuals with the ss genotype is less stable and has a reduced capacity to carry oxygen compared to hemoglobin in individuals with the AA genotype. This reduced oxygen-carrying capacity can lead to sickle cell disease, a genetic disorder characterized by the formation of sickle-shaped red blood cells and various health complications.
It's important to note that the differences mentioned above are specific to the beta-globin protein and the hemoglobin molecule. The ss genotype can have broader implications for an individual's health, particularly if it leads to sickle cell disease, but the specific effects can vary depending on the individual and the severity of the condition.