Body Fluids and Circulation Question 10

10. ABO blood groups in humans are controlled by the gene I. It 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) Three

(b) One

(c) Four

(d) Two

Show Answer

Answer : c

Hints & Solutions

(c) The three alleles in ABO blood groups in humans can produce six different genotypes and four different phenotypes.

Genotypes Phenotypes
$I^{A}, I^{A}, I^{A} i$ Blood group $A$
$I^{B} I^{B}, I^{B} i$ Blood group $B$
$I^{A} I^{B}$ Blood group $AB$
$i i$ Blood group $O$