AP BIOLOGY

Detailed explanation-1: -A woman who is a carrier has: a 25% (one in four) chance of having a daughter who is a carrier. a 25% chance of having a son with hemophilia. and a 50% chance of having a child (boy or girl) who does not have the gene for hemophilia at all (Figure 2.5)

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: -If the mother is a hemophilia carrier, there is a chance that the baby will be born with hemophilia. In families with a known history of hemophilia, or in those with a prenatal genetic diagnosis of hemophilia, one can plan special testing for hemophilia before the baby’s delivery.

Detailed explanation-4: -When a female has one affected X chromosome, she is a “carrier” of hemophilia. Being a female carrier of hemophilia is not the same as having hemophilia, although female carriers may experience symptoms of hemophilia. A female carrier can also pass the affected X chromosome on to her children.

Detailed explanation-5: -Hemophilia types A and B are inherited diseases. They are passed on from parents to children through a gene on the X chromosome. Females have two X chromosomes, while males have one X and one Y chromosome. A female carrier has the hemophilia gene on one of her X chromosomes.