A man with hemophilia is married to a healthy woman whose father is hemophilic

A man with hemophilia is married to a healthy woman whose father is hemophilic № is it possible to have healthy children? In this case, will the woman be a carrier of hemophilia?

Let’s designate the chromosome in which the gene that causes the development of hemophilia is inherited as X h. A chromosome with a gene that causes normal blood clotting in humans will be designated X H.

The father of a woman with hemophilia had the X h Y genotype. He produced two types of spermatozoa – X h and Y. He could pass on to his daughter only the X h chromosome (with a pathological gene in its composition). Hence, a healthy woman is heterozygous. She has the genotype X H X h, and produces two types of eggs – X H and X h.

A man with hemophilia, like a woman’s father, has the X h Y genotype and produces sperm cells X h and Y.

The offspring, theoretically possible in a given married couple, is represented by the following options:

healthy girls – carriers of the pathological gene (X H X h) – 25%;

girls with hemophilia (X h X h) – 25%;

healthy boys (X H Y) – 25%;

boys with hemophilia (X h Y) – 25%.

Answer: 1) the woman will be a carrier of hemophilia; 2) the probability of having healthy children in a given family will be 50%.