Question

Harry and Ginny both have freckles (a dominant trait), but their son does not. a. Show with a Punnett square how this is possible. b. If they have two more children, what is the probability (%) that BOTH will have freckles.

Answer 1

Using a Punnett square, it is possible for Harry and Ginny to have a son without freckles if they are both heterozygous for the freckles trait. The probability that both of their future children will have freckles is approximately 56%.

Step-by-step explanation:

To show how it is possible for Harry and Ginny to have a son without freckles, we can use a Punnett square to analyze their genotypes. Let's assume that both Harry and Ginny are heterozygous for freckles, meaning they each have one dominant allele (F) for freckles and one recessive allele (f) for no freckles. The Punnett square would look like this:

F x F

F | FF | Ff

f | Ff | ff

As shown in the Punnett square, there is a 25% chance that the child will inherit two recessive alleles (ff) and therefore not have freckles. This explains how their son does not have freckles even though both parents do.

If Harry and Ginny have two more children, the probability that BOTH will have freckles can be determined by using the same Punnett square. Since both parents are heterozygous (F), the probability of each child inheriting a dominant allele (F) for freckles is 75%. Therefore, the probability of both children inheriting a dominant allele is 75% x 75% = 56.25% or approximately 56%.

Learn more about Punnett square