Class 12th Biology 2013 Set2 Delhi Board Paper Solution

Question 25

(a) Why is human ABO blood group gene considered a good example of multiple alleles?
(b) Work out a cross up to F1 generation only, between a mother with blood group A (Homozygous) and the father with blood group B (Homozygous). Explain the pattern of inheritance exhibited.

Answer
(a) ABO blood group is controlled by I gene.
      I genes has 3 alleles IA, IB, i
      Therefore ABO blood group is a good example of multiple allelism
 
(b) Genotype
 
Genotype
 
So Progeny will have blood group AB.
– This shows codominance pattern of inheritance.