This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
After a point mutation, glutamic acid is replaced by valine, which leads to formation of sickle cell hemoglobin. The mobility of HbS as compared with normal hemoglobin on gel electrophoresis will be: 
Select and explain. 
A. Decreased, B. Increased, C. Dependent on HbS concentration, D. Unchanged.
A: Decreased
Answer: A: Decreased 
Explanation: HbS mobility on gel electrophoresis:Decreased mobility - Compared to normal hemoglobin.Electrophoresis of hemoglobin:Obtained from lysed red blood cells.Used in sickle cell trait & disease diagnosis.Sequence of Movement: HbA2 < HbC < HhS < HbF < HbA