Question

A woman with normal blood clotting mates with a man who has hemophilia. Their first child is a boy who has hemophilia. Tests show that the father and son both have the same form of hemophilia, that it is X-linked, and that the boy has normal genetic inheritance. You can predict that if the couple has more children together, it is likely that ____.

Answer 1

half of the boys and half of the girls will have hemophilia.

Step-by-step explanation:

Haemophilia is a disorder in blood clotting. For example: When we cut off some part of our body and it starts to bleed, proteins (elements responsible for the growth and development of all body tissues) take action to stop the bleeding. This process is called coagulation. People with hemophilia do not have these proteins and therefore bleed more than normal.

Hemophilia is a genetic disease, ie, it is transmitted from parents to children at the time the child is born. In the case exposed in the question, we can see that father and son have X-linked hemophilia, while the mother has normal coagulation. For this reason, assuming that this couple has more children, half of the boys and half of the girls will have hemophilia, since the father has hemophilia and the mother has normal coagulation.

Answer 2

They would give birth to carrier females and healthy males

Step-by-step explanation:

The gen for haemophilia has an X-linked recessive pattern, therefore all descendant males for these couple will not inherit the gen, because they will receive the Y from the father and the X from the mother, if the couple have girls, all the female descendants will inherit the recessive gen.

X Y

X XX XY

X XX XY

But in this case they had a boy with the haemophilia gen, meaning that the mother has a recessive gen for haemophilia and in this case, they will have 25% change to give birth to a healthy boy, 25% chance to give birth to a girl with recessive pattern (carrier) and 25% to give birth to a girl with dominant pattern (affected).

X Y

X XX XY

X XX XY

XX (carrier girl)

XY (healthy boy)

XY (affected boy- first child)

XX (affected girl)