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Shepard

  • 3 years ago

Hemophilia is a blood clotting disorder that is a sex-linked trait carried on the X chromosome. If a woman with hemophilia and a man without the disorder have two sons and two daughters, how many of their children would have hemophilia None One Two Four

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  1. blues
    • 3 years ago
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    Do a Punnett square. The first step is come up with names for your alleles. The woman has two X chromosomes and the man has one X and one Y chromosome. Because the woman has hemophilia and hemophilia is recessive, both her X chromosomes must have the hemophilia allele for her to have the disease. So you can label that particular allele Xh for X (the chromosome it is on) and h (the hemophilia allele). Her genotype is Xh Xh. The Dad does not have hemophilia, so he must have a normal X allele. His genotype is XY. These are the genotypes you should use in your Punnet square. Helpful?

  2. Shepard
    • 3 years ago
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    What is a Punnett square, I fear I may have not learned that yet, or do not remember. Should I just google it?

  3. blues
    • 3 years ago
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    Wikipedia would be better than Google. The Punnett Square for this cross looks like this: |dw:1351204642593:dw| The Mom's alleles are on the top, the Dad's alleles are on the side and the offspring's alleles will be in the squares.

  4. Shepard
    • 3 years ago
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    Oh, ok! I think I got it now.

  5. blues
    • 3 years ago
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    Cool. :)

  6. Shepard
    • 3 years ago
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    Just to make sure, because I have to try it out a few times before fully understanding it, the answer would be two right?

  7. Shepard
    • 3 years ago
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    Or none, I think I may have misunderstood the process on doing it.

  8. blues
    • 3 years ago
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    When you fill in the offspring's genotypes in the Punnet square, what happens? What does it look like?

  9. Shepard
    • 3 years ago
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    I got none because since the father has zero h to complete the Xh. Or can the Xh be passed down, directly from her to the children

  10. blues
    • 3 years ago
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    The mother will give a Xh allele to all of her offspring. The daughters will have a second, normal X from Dad. So they will be carriers, but won't have hemophilia because they have that normal X. The sons will get a Y from Dad. They will only have the Xh from Mom. So because they do not have a normal X (i.e., if they had a second X, they would be girls), they will all have hemophilia. So both sons will have it, neither daughter will have it.

  11. preetipooja
    • 3 years ago
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    2

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