AP BIOLOGY

Detailed explanation-1: -A daughter will get either her mother’s X chromosome with the hemophilia gene or her mother’s X chromosome with the normal gene for clotting. If she gets the X chromosome with the hemophilia gene she will be a carrier. So a carrier’s daughter has a 50% chance of being a carrier.

Detailed explanation-2: -If a mother is heterozygous (a carrier) for hemophilia and the father does not have hemophilia, each son has a 1 in 2 (50%) chance of getting his mother’s hemophilia allele and having hemophilia. Each daughter has a 1 in 2 (50%) chance of getting her mother’s hemophilia allele and being heterozygous.

Detailed explanation-3: -A female who is a carrier has a 50-50 chance that each male child will have hemophilia. There is a 50-50 chance that each female child will be a carrier (Picture 2).

Detailed explanation-4: -Yet, women and girls make up a smaller proportion of patients with severe or moderate hemophilia, ranging from less than 0.5% to a little more than 1%.

Detailed explanation-5: -If both parents have the changed gene If a woman with the changed gene and a man with haemophilia have a baby, there’s a: 1 in 4 chance of having an unaffected baby boy. 1 in 4 chance of having a baby boy with haemophilia. 1 in 4 chance of having a baby girl who’s a carrier of haemophilia.