Answer:
a) 1:4 (25%)
b) 1:4 (25%)
c) Carrier females have the genotype XFXf.
d) There are four possible genotypes, XFXf, XfXf, XFY, XfY
Explanation:
The mutation for hemophilia is on the X chromosome. Females have two X chromosomes and males have one.
Let's say that the mutated allele is f and the normal allele is F.
A carrier female has the genotype XFXf. A hemophilic man has one X chromosome. and since he is affected, must have the mutated allele. He must have the genotype XfY.
The punnett square below shows the cross
XF Xf
Xf XFXf XfXf
Y XFY XfY
a) As we saw, carrier females have the genotype XFXf. In the cross, there 1:4 chance that phenotype will occur.
b) A normal male has the genotype XFY. In the cross, there 1:4 chance that phenotype will occur.
c) Carrier females have the genotype XFXf.
d) There are four possible genotypes, XFXf, XfXf, XFY, XfY
