Question

In humans, freckles are inherited via a simple Mendelian pattern. A male is heterozygous for freckles, and he has freckles. He marries a woman who is also heterozygous for freckles, and they have children. Each time they have a child, this person as a ______ percent chance of being freckled and a __________ percent chance of being heterozygous for the trait.

Answer 1

Each child of a couple who both carry heterozygous freckle traits has a 75% chance of being freckled and a 50% chance of being heterozygous for freckles.

Step-by-step explanation:

When a male and a female who are both heterozygous for freckles (which is an autosomal dominant trait) have children, the offspring have different probabilities of inheriting the trait.

According to Mendelian genetics, and assuming freckles (F) are dominant to no freckles (f), the parents' genotypes are Ff for both the mother and the father. Using a Punnett square, we can predict the outcomes of their offspring's genotypes:

• FF (homozygous dominant)
• Ff (heterozygous)
• fF (which is the same as Ff, heterozygous)
• ff (homozygous recessive)

From this genotypic ratio of 1:2:1, we can infer the phenotypes of the children. Since freckles are dominant, both FF and Ff individuals will have freckles. Therefore, the chance of being freckled (either FF or Ff) is 75% (3 out of 4), and the chance of being heterozygous (Ff) for the trait is 50% (2 out of 4).

So, each child they have has a 75 percent chance of being freckled and a 50 percent chance of being heterozygous for the trait.