Match the Column I with Column II:
| Column I | Column II |
| A. Colour blindness | i. RBCs become sickle-shaped under low O₂ tension |
| B. Haemophilia | ii. Mutation on HBA1 and HBA2 genes on chromosome 16 or HBB gene on chromosome 11, causing abnormal haemoglobin |
| C. Sickle-cell anaemia | iii. Sex-linked recessive disorder where affected person cannot distinguish between red and green |
| D. Thalassemia | iv. Sex-linked recessive disorder preventing blood clotting |
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) - A - iii, B - iv, C - i, D - ii
| Column I | Column II |
| A. Colour blindness | iii. Sex-linked recessive disorder where affected person cannot distinguish between red and green |
| B. Haemophilia | iv. Sex-linked recessive disorder preventing blood clotting |
| C. Sickle-cell anaemia | i. RBCs become sickle-shaped under low O₂ tension |
| D. Thalassemia | ii. Mutation on HBA1 and HBA2 genes on chromosome 16 or HBB gene on chromosome 11, causing abnormal haemoglobin |
Colour blindness: Sex-linked recessive disorder caused due to mutation in genes present on X-chromosome. Mostly females are carrier while males contract the disease. Affected person fails to discriminate red and green colour.
Haemophilia : Sex-linked recessive disorder which prevent clotting of blood. Heterozygote females are carrier who transmit the disease to sons.
Thalassemia. Autosome linked recessive trait. α-thalassemia is caused due to the mutation in HBA1 and HBA2 genes on chromosome 16. β-thalassemia is caused due to the mutation in HBB gene on chromosome 11. The rate of synthesis of α or β-chain gets reduced leading to the formation of abnormal haemoglobin.
Sickle-cell anaemia: Autosome linked recessive trait. Caused due to the substitution of glutamic acid by valine as the sixth codon of β-globin gene gets substituted from GAG to GUG. RBCs become sickle-shaped under low O2 tension.