Hemophilia is a sex-linked recessive trait. A phenotypically normal woman has phenotypically normal parents. However, she has a hemophiliac brother. What are the genotypes of her parents? What are her chances of being a carrier for hemophilia? If she is a carrier and marries a male with hemophilia, what is the chance of a child being a hemophiliac?

A. parents: Hh and Hh

B. chances of being a carrier: 50%

C. 50%

Explanation:

A. Since hemophilia is a recessive trait, both parents must carry the recessive alelle for it to show through in the child. However, we know both of them are phenotypically normal, meaning a dominant trait (not hemophiliac, H) is masking the recessive trait (hemophiliac, h)

B. The options the woman has when you create a punnet square with her parents genotypes are HH (doesn't have any hemophilia, because hemophilia is recessive, so represented with a lower case h) Hh (there is twice the likeliness she is an Hh since it occurs two times when you combine her parents genotypes. Hh means she is a carrier, but does not have the trait) and hh (meaning she definitely has it). So there is four options, two of which mean carrier, meaning she has a 50% chance of being a carrier.

C. genotypes of the parents:

mom: Hh

dad: hh

when you create their punnet square, you will get two occurrences of Hh and two occurrences of hh. Remember that hh means hemophilia. This means the child has a 50% chance of having hemophilia.

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).

the wires in the toaster turning red and the toast crisping and turning brown