Question

Cross a person who does not have freckles and is heterozygous for dimples with a person who has
freckles (but her mom does not) but no dimples.
1. What is the probability that these parents will have a child with dimples?
2. What is the probability that these parents will have a child with freckles?
3. What is the probability that these parents will have a child with dimples and freckles?

Answer 1

Answer:

1. 1/2

2. 1/2

3. 1/4

Explanation:

Let the allele for freckles be A or a while that of dimples be B or b.

A person without freckles but heterozygous for dimples = aaBb

A person who has freckles (whose mother has no freckles) but no dimples = Aabb

      aaBb    x    Aabb

Offspring

4 AaBb - freckled and dimpled

4 Aabb - freckled and non dimpled

4 aaBb - non freckled and dimpled

4 aabb - non freckled and non dimpled

1. Probability that the parents will have a dimpled child = 8/16 or 1/2

2. Probability that they will have a child with freckles = 8/16 or 1/2

3. Probability that they will have a child with freckles and dimples = 4/16 or 1/4

See the attached image for the Punnet's square analysis of the cross