Question

Choose the correct answer from the alternatives given.

ABO blood groups in human beings are controlled by the gene l. The gene l has three alleles $I^A,I^B$ and $i$. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?

• A. 6
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is D 4

In human beings, ABO blood groups are controlled by gene $I$ which has three alleles $I^A,I^B$ and $i$. The six possible genotypes are $I^A{I}^A,I^A{I}^B,I^{A}i,I^B{I}^B,I^{B}i$ and $ii$. The phenotypes which occur by these genotypes are $A(I^A{I}^A,I^{A}I),B(I^B{I}^B,I^{B}i),AB\left(I^A{I}^B\right)$ and $O\left(ii\right)$.