Question

Which is a best example of point mutation :

• A. Colour blindness
• B. Thalassemia
• C. Alkaptonuria
• D. Sickle-cell-anemia

Answer 1

The correct option is D Sickle-cell-anemia

In point mutation changes occur in a single base pair of DNA. Sickle cell anemia is the best example for point mutation (insertion or deletion occur in a single base pair. In this disease in the globin protein of our respiratory pigment 'haemoglobin' a defect occurs.

Color blindness is inherited as a recessive trait on the X chromosome. This is known in genetics as X-linked recessive inheritance. As a result, the condition tends to affect males more often than females

Thalassemia is a group of blood disorders which are caused by mutations in the HbB and HbA genes present on chromosome 11 and chromosome 16 respectively. The unequal crossover within globin gene complexes causes deletion which in turn leads to backward shifting of the reading frame. Thus, the disease is caused by a frameshift mutation.

Alkaptonuria is a rare inherited disorder. It occurs when your body can't produce enough of an enzyme called homogentisic dioxygenase (HGD).

So, the correct answer is "option C"