A couple has just learned that their daughter has hemophilia. They already have a son who does not have the disease. What are the genotypes of the couple? Explain your reasoning.
I'm really stuck on this question, it's my last one and I've been looking at my textbook for a while trying to figure it out, but I still don't understand.
I need to know the couple stuff I have the reasoning I think I’m right in it all be I want to be sure...
To determine the genotypes of the couple, we need to understand the inheritance patterns of hemophilia. Hemophilia is an X-linked recessive genetic disorder, meaning it is carried on the X chromosome.
Since the couple has a son who does not have hemophilia, we can conclude that the son inherited a Y chromosome from his father, as males inherit their Y chromosome from their fathers. Therefore, the father is not a carrier of the hemophilia gene.
However, the daughter has hemophilia, which means she received a copy of the hemophilia gene. Females have two X chromosomes, one inherited from each parent. In this case, the mother must have at least one X chromosome carrying the hemophilia gene.
Given that the father is not a carrier of the hemophilia gene, we can infer that he is normal in this context. We represent the normal gene as "X^N" (X-normal), where '^' indicates the father's genotype.
Now, let's consider the mother. She must have at least one X chromosome carrying the hemophilia gene. We represent the hemophilia gene as "X^h."
With this information, we can deduce the possible genotypes for the couple:
Father: X^N Y
Mother: X^h X^N or X^h X^h
The father's genotype is X^N Y because he is unaffected by hemophilia. The mother's genotype can either be X^h X^N or X^h X^h since she has a daughter with hemophilia. In both cases, the mother is a carrier of the hemophilia gene.
It's important to note that the genotypes presented are only possible options based on the information provided. Additional information or testing may be needed for a more accurate determination of the genotypes.