So the probability of this would be, a big
old zero. Now why is that? Well, we know that
if the mother is homozygous and unaffected, it means that
she is homozygous, and she has the dominant normal alleles.
The father is affected, so he must have a recessive
allele on the X, and nothing on the Y. Well,
of all the possible combinations that could happen, the father
could pass on the Y, and you'd get a boy.
But the mother's going to give an X in
both of those cases, and both of her X's are,
are dominant, non color-blind alleles, so the son is
going to be regular color vision. The father can pass
on the recessive allele from his X. But if
he does, the mother's just going to pass on the dominant
allele from one of her Xs. So you, at the
very most, be a carrier but you wouldn't be affected.
Таким образом, вероятность этого будет больше
чем ноль. Но, почему так? Ну, мы знаем, что