Mutation leading to sickle cell anemia?

Ans. is D i.e., Point mutation. Sickle cell anemia is a hereditary hemoglobinopathy, i.e., the type of disease characterized by production of defective hemoglobin. Sickle cell anemia results from mutation in b-globin gene. It is caused by a point mutation (Base substitution mutation) at the sixth position of the b-globin chain leading to subsitution of a valine residue for a glutamic acid residue resulting in sickle hemoglobin (HbS). Sickle cell anemia is an autosomal recessive disorder. If an individual is homozygous for the sickle cell mutation, almost all the hemoglobin in the red cell is HbS. In heterozyogotes, only about 40% of the hemoglobin is HbS, the remainder being normal hemoglobins.