Sickle-cell disease is probably the result of which kind of mutation?

The question is incorrect as it does not have the options which are:

A) point

B) frameshift

C) nonsense

D) nondisjunction

E) both B and D

Point mutation

Explanation:

Sickle cell disease refers to the disease which is caused by the change in the shape of the oxygen delivering cell in the blood called the red blood cells.

The shape of the red blood cells becomes crescent of sickle due to the distortion in the shape of the hemoglobin molecule which binds oxygen.  The distortion in the shape of the hemoglobin molecule is genetically controlled and occurs when the person possesses both the copies of the allele which changes the shape.

The mutated gene changes the shape of the hemoglobin by changing the glutamic acid amino acid by valine at the 6th position. Since the mutation changes the amino acid at only one position that is only 6th position therefore it is considered a point mutation.

Thus, a point mutation is correct.