CBSE Class 12-science Answered

Thalassemia is a group of genetic blood disorders that are characterized by reduced or absent synthesis of one or more of the globin chains of hemoglobin. Myoglobin is a protein found in the muscle tissue which is involved in oxygen storage. Thalassemia is not caused due to abnormal myoglobin chain synthesis. So, Assertion (A) is false.

Alpha thalassemia is caused by mutations in the HBA1 and HBA2 genes located on chromosome 16, which encode the alpha globin chains of hemoglobin. These mutations can lead to reduced or absent synthesis of alpha globin chains, resulting in the formation of abnormal hemoglobin molecules and a range of clinical symptoms. So, the Reason (R) is correct.