Answer: The mother of the man can be either XHXH or XHXh and pass her normal allele to the son and his father can be either XHY or XhY, he only passes his Y chromosome. The mother of the woman can be XHXH or XHXh and the father could be XhY, then she could have inherited the normal allele from the mother and the affected allele from the father. But also, the mother of the woman could be XHXh or XhXh and the father could be XHY, so in this case she could have inherited the normal alele from the father and the affected allele from the mother.
Explanation:
Hemophilia is an inherited bleeding disorder in which the blood does not clot properly. This can cause bleeding either spontaneously or after an injury.
<u>It is related to the X chromosome and it is recessive for females</u>, this mean they need both affected alleles to develop the trait. <u>Males only need one recessive allele because they only have one X chromosome</u>. This means that females need both parents to be at least carriers (although one or both can also have the disease or both recessive alleles). While males inherit it only from the mother, either she is a carrier (one recessive allele) or she has the disease (both recessive alleles). Then the mother passes the X chromosome with the affected allele to the son, and that son only receives the Y chromosome from the father, which does not have the gene that determines this disease.
If the mother is a carrier, her genotype is XHXh, being XH the normal allele and Xh the affected allele. She does not have hemophilia because she has a dominant allele. The father is XHY, so he does not have the disease because his only allele is normal (dominant)
The mother of the man can be either XHXH (she can only pass a normal allele) or XHXh and pass her normal allele to the son (in this case, the recessive allele is not inherited by chance.) His father can be either XHY or XhY, he only passes his Y chromosome which is not related to the disease. The mother of the woman can be XHXH or XHXh and the father could be XhY, then she could have inherited the normal allele from the mother and the affected allele from the father. But also, the mother of the woman could be XHXh or XhXh and the father could be XHY, so in this case she could have inherited the normal alele from the father and the affected allele from the mother.
