Question

Brown eyes in humans are dominant to blue eyes. A brown-eyed man, whose mother was
blue-eyed, marries a brown-eyed woman whose father had blue eyes. What is the probability that this couple will have a blue-eyed child?

Answer 1

Answer:

Sorry but I didn't get it

Answer 2

Your parents are both heterozygous for the pigment-producing gene that makes the iris brown. Each had a parent devoid of the pigment gene, so neither could have inherited a pigment gene from both parents. Name the dominant pigment allele A and the inactive allele a.The man and woman are both Aa-one of each allele. It only takes one Aallele to give brown eyes. Each parent gives a child one allele.

There is therefore one chance in four for each of these possibilities: one allele from each parent, in order:
AA (brown eyes)
Aa (brown eyes)
aA (brown eyes)
aa (blue eyes)

Therefore there is a 1:4 chance of having a blue-eyed child.