Principles of Inheritance and Variation Question 10

10. The genotypes of a husband and wife are $I^{A} I^{B}$ and $I^{A} i$.

Among the blood types of their children, how many different genotypes and phenotypes are possible?

(a) 3 genotypes; 4 phenotypes

(b) 4 genotypes; 3 phenotypes

(c) 4 genotypes; 4 phenotypes

(d) 3 genotypes; 3 phenotypes

Show Answer

Answer : b

Hints & Solution

(b) Husband $\times$ Wife $I^{A} I^{B}$

$\sigma^{2}$ $I^{A}$ $I^{B}$
$I^{A}$ $I^{A} I^{A}$ $I^{A} I^{B}$
$i$ $I^{A} i$ $I^{B} i$
Number of genotypes $=4$
Number of phenotypes $=3$
$I^{A} I^{A}$ and $I^{A} i=A$
$I^{A} I^{B}=AB$
$I^{B_i}=B$