Question

A man has blood type O, Rh negative. These are both recessive traits. He is married to a woman who has blood type A, Rh positive. These are both dominant traits. Blood type and Rh factor are not linked genes. This couple has 3 children, two type A, Rh positive and one type A, Rh negative. What is the mother's most likely genotype? A) IAIARR B) IAIARr C) IAIORr D) IAIArr

Answer 1

Mother genotype is IAi (heterozygous)

Explanation:

Man is Rh negative and O type blood group its genotype is OrOr

Mother is A positive so her genotype would be either IAIA or IAi

Also A blood group is dominant over O blood group.

It is given:

two children are A POSITIVE

One child is A negative

so the mother must have been heterozygous with genotype IAi as one of the child would have recieved it from mother as it is a dominant trait.

Punnete square shows

       AI   Ai

i     AIi   Aii

i     AIi   Aii    50 percent chances of A negative child is there.