Genetics linkage question: is this woman a carrier?
Given: Hemophilia and colorblindness are 10 units away from each other on the X chromosome (i.e. they are sex-linked and, if a chromosome has both of them, there is only a 10% chance that they will be inherited separately).
A colorblind man married a woman who has one 'clean' X and one X that carries both hemophilia and colorblindness. They have a colorblind daughter. What are the chances that
1-she is a carrier of hemophilia and
2-she will pass the disease on to a future son?
This isn't a pure Mendelian question, this is about linkages.
I know that the answer to the first part is that she has a 90% chance of carrying hemophilia. (I did a punnet's square and got 4 possibilities:
1-daughter got the 'clean' X: no hemophilia, no colorblindness
2-daughter got the X with hemophilia and colorblindness
3-daughter got a 'crossover' X: colorblindness, but no hemophilia
4-daughter got a 'crossover' X: hemophilia, but no colorblindness
Options 3 and 4 together have a 10% chance of happening, meaning each one only has a 5% chance (and meaning that the other options have a combined 90% chance of happening, or 45% each).
She could only be option 2 or 3 (because she is colorblind and those are the only ones that result in colorblindness), so she has a 90% chance of option 2 and a 10% chance of option 3.
But I still don't know the chances of passing it on to her son (other than the fact that it is NOT).
50% and my teacher seemed to indicate that it isn't 45% (my first guess) either).