Sex-linked Traits (punnett square)?

I've attempted this one but I am having trouble still. I read the section in my book, the wikipedia article, and more but would like to double check my work here.





Sex-linked traits: traits transmitted on the X or Y chrom. Most sex-linked traits are found on the X chrom. A female, with two X chroms will carry a pair of alleles, while a male, with only one X chrom, carries a single allele. make sure to show XX for emale and XY for male. Then give another lable for the trait you are examining. Example X^R X^r.





Hemophilia is inherited as an X-linked recessive. A male who is hemophiliac marries a female who is not afflicted (homozygous).





a. What is the probability their 1st child will be a hemophiliac?


b. What is the probability that they will have a son who is a hemophiliac?





Ok...this is what I have so far:





X^R X^R(mother) x X^r Y (father)





.............X^r............. Y


X^R.....X^R X^r....X^R Y


X^R.....X^R X^r....X^R Y





So far so good? Now I just need to do the probabilities, yes?

Sex-linked Traits (punnett square)?
Yes, so far so good.


On with the probabilities!





a. 0%


b. 0%
Reply:Looks good to me


a. Zero chance


b. Zero chance