Question

hemophilia is a sex-linked recessive trait. if a male parent does not have hemophilia and a female parent is a carrier, what is the probability of a couple having a female offspring with hemophilia? type your answer... % fraction:
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8 multiple choice 1 point
hemophilia is a sex linked recessive trait if a couple knows that their daughter has a 100% chance of having hemophilia what are the genotypes of the parents?

Explanation:

Step1: Define parent genotypes

Male (unaffected): $X^H Y$; Female (carrier): $X^H X^h$

Step2: List female offspring genotypes

From cross $X^H Y \times X^H X^h$, female offspring get one X from each parent: $X^H X^H$, $X^H X^h$

Step3: Check for hemophilia in females

Hemophilia requires $X^h X^h$; no female offspring has this genotype. Probability = 0.

Step4: Identify parents for 100% affected daughters

Daughters get X from each parent. For 100% affected ($X^h X^h$), father must pass $X^h$ (so father is $X^h Y$, affected) and mother must only pass $X^h$ (so mother is $X^h X^h$, affected).

Answer:

1. Probability of female offspring with hemophilia: 0% or $\frac{0}{1}$
2. Genotypes of parents for 100% affected daughters: Father: $X^h Y$ (hemophiliac male), Mother: $X^h X^h$ (hemophiliac female)