Hemophilia is caused by an x-linked recessive mutation in humans. if a woman whose paternal uncle (fathers brother) was a hemophiliac marries a man whose brother is also a hemophillac, what is the probability of their first child having hemophilia (note: assume that there are no other cases of hemophila in the pedigree and no hidden carriers)? select one: o a. 1/2 o b. 1/8 o c.0 o d. 1/4 o e. 1

c. 0

Explanation:

The probability of their first child having hemophilia is 0.

Since hemophilia is is an X-linked and recessive, a man will either be affected or not affected while a woman can be affected, unaffected or be a carrier of the disease.

If the paternal uncle (not the father) of a woman is hemophilic and there is no history of the disorder in the woman's mother's family, such woman is unaffected for the disorder. Hence, her genotype will be (assumming the allele for hemophilia is represented by h).

A man whose brother is hemophilic without himself being hemophilic will have the genotype .

Crossin the two in marriage:

  x  

progeny:

None of the progeny will have hemophilia.

Hence, the probability of their first child having hemophilia is 0.

The correct option is c.