Question

​A father has blood group A and a mother has blood group O. Their son has blood group O. So can it be said that O blood group is a dominant trait? why or why not ? Explain. (3 marks)

Answer 1

Dear student ,

Father having blood group A can have one of the Following genotype -
I^AI^A or I^AI^O
Mother having blood group O has the following genotype -
I^OI^O
So , when offspring is formed , it may have either of the following genotypes -
1. If the father is I^AI^A and Mother is I^OI^O
Then the child will have I^AI^O genotype and hence A blood Group.

2. If the father is I^AI^O and Mother is I^OI^O
then the child will have I^AI^O or I^OI^O genotype and hence can have either of A or O blood group.

Therefore , it can be seen that here A is more likely to occur than O blood group
Hence we can say that O is not dominant.

Regards!