Assertion (A): Thalassemia is passed on from parents to the progeny when both the partners are heterozygous (unaffected carrier) for the gene.
Reason( R): Production of `alphaandbeta` globin chain is affected in `alpha` Thalassemia and the `beta` Thalassemia.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and Rare true but is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true

Answer

A

Explanation

(1) The cause of the disease can be either mutation or deletion.
(2) The mutation results in reduced rate of synthesis of one of the globin chains (and chains) of haemoglobin.
(3) This results in the formation of abnormal haemoglobin molecules causing anaemia.
Thalassemia can be classified as:
(1) Thalassemia: In this the production of globin chain is affected. Two closely linked genes HBA1 and HBA2 on chromosome 16 of each parent controls Thalassemia.
(2) Thalassemia: in this the production of `beta` globin chain is affected. A single gene HBB on chromosome 11 of each parent controls `beta` Thalassemia.