Question

A male is heterozygous for the trait that produces freckles on the skin, and he has freckles. if he marries a woman who is also heterozygous for freckles, ______ percent of their children are predicted to be freckled. also, of all their children, ______ percent are predicted to be heterozygous.

Answer 1

F- allele for freckles
f- allele without freckles

1) The man is heterozygote and has freckles, its indicating that the allele for freckles is dominant.
A cross between him and a woman who is also heterozygote: Ff x Ff
it would result in the following probabilities:
- 1/4 - homozygote with freckles: FF
- 2/4 - heterozygote with freckles: Ff
- 1/4- homozygote without freckles:ff

Their son would have a probability of 75% of being born with freckles.


2) The cross resulted in this probabilities:
- 1/4 - homozygote with freckles: FF
- 2/4 - heterozygote with freckles: Ff
- 1/4- homozygote without freckles:ff
So, the chance of being born heterozygote for this gene is 2/4, which is the same as half (50%).