Question

A child of O blood group, has B-blood group father, the genotype of father would be

• A. $I^O{I}^O$
• B. $I^B{I}^B$
• C. $I^A{I}^A$
• D. $I^B{I}^O$

Answer 1

Answer: (D)

$I^B{I}^O$

Human blood group inheritance is the example of co-dominance and multiple alleles. It is governed by three alleles namely I${}^A$, I${}^B$ and I${}^O$. I${}^A$ and I${}^B$ show co-dominance while allele I${}^O$ is recessive to both I${}^A$ and I${}^B$. Genotype of a child with O blood group will be I${}^O$I${}^O$. Hence, the father should carry at least one I${}^O$ allele which makes options B and C wrong. The genotype in option A gives O blood group while the genotype in option D gives B blood group while satisfying the requirement of one I${}^O$ allele; thus, genotype of father would be I${}^B$I${}^O$.

Thus, the correct answer is option D.