17. Hemophilia is an inherited bleeding disorder were blood does not clot properly. This disorder is caused by a recessive allele on the X chromosome. 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 and the two siblings? Explain your answer.
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Hey just saying that's pretty unhelpful;(
Hey actually if you get some more help with that psydawg it helps a bit to understand
To determine the genotypes of the couple and their two children, we need to understand how the trait is inherited and the possible combinations of alleles.
Hemophilia is caused by a recessive allele on the X chromosome. In humans, females have two X chromosomes (XX) while males have one X and one Y chromosome (XY).
Let's assign the alleles for hemophilia:
- Normal allele (non-hemophilic): H
- Hemophilia allele (hemophilic): h
From the information given, the couple has a daughter with hemophilia and a son without the disease. Since the daughter has hemophilia, we can conclude that her genotype is "XhXh" because she inherited the recessive hemophilia allele from both parents. This means that her X chromosome from her mother must be the hemophilia allele (Xh), while her X chromosome from her father is also the hemophilia allele (Xh).
Now, let's determine the genotypes of the couple. The son does not have hemophilia, so he must have received a normal allele from either his mother or father. Since the father does not have hemophilia, we can conclude that his genotype is "XY". The Y chromosome does not carry the hemophilia allele, so the son does not have the disease.
Now, let's determine the genotype of the mother. Since the son does not have hemophilia and the mother is the only possible source of the normal allele, we can conclude that her genotype is "XHXh". This means that she inherited the normal allele (XH) from one parent and the hemophilia allele (Xh) from the other parent.
To summarize:
- Daughter's genotype: XhXh
- Son's genotype: XY
- Father's genotype: XY
- Mother's genotype: XHXh
Remember, this analysis assumes that the mother is a carrier for hemophilia and the father does not have the disease. It is always important to consult with a medical professional or genetic counselor for a comprehensive understanding of specific genetic conditions and inheritance patterns.
This should lead you to the answers.
Mom is a carrier and Dad is a hemophiliac. Since it is on the X chromosome, for a woman to be a hemophiliac, she must have two recessives, a man only needs one.