MP Board · Class 12 · Biology · Principles of Inheritance and VariationWhich of the following conditions represents a case of co-dominance in human beings?
The correct option is ABO blood grouping. In human beings, ABO blood groups are controlled by the gene $I$. The gene $I$ has three alleles $I^A$, $I^B$, and $i$. The alleles $I^A$ and $I^B$ produce a slightly different form of the sugar while allele $i$ does not produce any sugar. When $I^A$ and $I^B$ are present together, both express their own types of sugars because of co-dominance, resulting in AB blood type. Phenylketonuria is an inborn error of metabolism, hemophilia is a sex-linked recessive disease, and thalassemia is an autosomal recessive blood disorder, none of which represent co-dominance.
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Principles of Inheritance and Variation.
Correct choice. Refer to the step-by-step verified solution guidelines above for details.
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Principles of Inheritance and Variation.
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Principles of Inheritance and Variation.