Question

In heterozygous condition both the alleles are expressed in ................

• A. diabetes
• B. AB blood group
• C. colour blindness
• D. haemophilia

Hint:

In codominance, both alleles contribute equally to the phenotype, as seen in the AB blood group.

Answer 1

The Correct Option is B

Step 1: Understanding genetic expression.
In the case of AB blood group, both A and B alleles are expressed when a person is heterozygous (having one A allele and one B allele). This is an example of codominance, where both alleles are equally expressed.
Step 2: Analyzing the options.
(A) diabetes: Incorrect — Diabetes is not an example of codominance.
(B) AB blood group: Correct — Both alleles (A and B) are expressed in AB blood type.
(C) colour blindness: Incorrect — Colour blindness follows X-linked recessive inheritance, and the trait is expressed only when the individual has two recessive alleles.
(D) haemophilia: Incorrect — Haemophilia also follows X-linked inheritance, and it is typically expressed in males with a single recessive allele.
Step 3: Conclusion.
The correct answer is (B) AB blood group, where both alleles are expressed in a heterozygous individual.