Q16 of 30 Page 1

Write the possible genotypes of the following:

(a) The F1 progeny of a cross between a heterozygous tall pea plant and a dwarf pea plant.


(b) The woman whose son has blood group ‘O’ and her husband has blood group ‘A’.


(a) The genotype of a heterozygous tall pea plant is Tt.

The genotype of a dwarf pea plant is tt.


The cross between them is represented as-



Therefore, the possible genotypes are Tt (Tall) and tt (Dwarf).


(b) Since the son has the blood type ‘O’ his genotype should be ii.


This implies that he has to receive one ‘i’ allele from each parent.


This would mean that the genotype of the mother should be heterozygous to the gene I, i.e., she should contain allele ‘i along with any of the other alleles- IA, IB or i.


Therefore, the possible genotypes of the woman are, IAi, IBi and ii.


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