Sex-Linked Pedigrees Worksheet illustrating inheritance patterns of hemophilia, a recessive X-linked disorder, with genotype notations for each individual.

Let’s solve this step by step.

We are told that hemophilia is a recessive sex-linked disorder on the X chromosome. That means:

- Males have one X and one Y → so if they get the bad allele (X^h), they will have the disease.
- Females have two X chromosomes → they need TWO bad alleles (X^h X^h) to have the disease. If they have one good and one bad (X^H X^h), they are carriers but don’t show symptoms.
- Shaded = has the disorder.
- Unshaded = does not have the disorder (could be normal or carrier).

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Look at individual #1: male, unshaded → he does NOT have hemophilia → his genotype must be X^H Y

Individual #2: female, unshaded → she does NOT have hemophilia → but look at her children: sons #4 and #5 ARE shaded (have hemophilia). Since males get their X from mom, that means mom (#2) must have given them an X^h. So she must be a carrier → X^H X^h

Now let’s go generation by generation.

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Generation I:

- #1: Male, unaffected → X^H Y
- #2: Female, unaffected, but has affected sons → must be carrier → X^H X^h

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Generation II:

Children of #1 and #2:

Possible combinations from parents:

Mom (X^H X^h) can give either X^H or X^h
Dad (X^H Y) gives X^H to daughters, Y to sons

So:

Daughters:
- Get X^H from dad + X^H from mom → X^H X^H → unaffected, not carrier
- Get X^H from dad + X^h from mom → X^H X^h → unaffected, carrier

Sons:
- Get Y from dad + X^H from mom → X^H Y → unaffected
- Get Y from dad + X^h from mom → X^h Y → affected

Now match to pedigree:

#3: female, unshaded → could be X^H X^H or X^H X^h — we’ll check later based on her kids.

But wait — in the diagram, under #3 it says “X^H X^H” — so maybe that’s already filled? Let me re-read the problem.

Actually, looking again — the user image shows some genotypes already written below each person. But since you’re asking me to solve it, I think those might be answers already provided? Or perhaps placeholders?

Wait — no, the instruction says: “Write in the genotypes on the line next to / below each individual.”

And in the image, under each person there IS a blank with something like “___ ___” — and for example, under #1 it says “X^H Y”, under #2 “X^H X^h”, etc.

BUT — actually, looking closely, I think those are the CORRECT answers already printed? Because under #3 it says “X^H X^H”, under #4 “X^h Y”, etc.

Wait — maybe the student is supposed to fill them in, and the image shows what should be there? Or maybe it's part of the worksheet showing correct answers?

This is confusing.

Let me read the original question again:

> 1) Hemophilia is a recessive sex-linked disorder... Write in the genotypes on the line next to / below each individual.

Then the pedigree is shown with blanks under each number.

In your uploaded image, under each person, there IS text like “X^H Y” under #1, “X^H X^h” under #2, etc.

I think those are the intended correct answers — meaning the worksheet already has the answers filled in as examples? Or maybe it’s interactive?

But since you’re asking me to solve it, I’ll assume we need to verify or derive them.

Alternatively — perhaps the blurred parts at bottom are questions about phenotypes, and the top part is where we write genotypes.

Given that, let’s just derive all genotypes logically.

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Start over cleanly.

Parents: #1 (male, unshaded) and #2 (female, unshaded)

They have:

- Daughter #3: unshaded
- Son #4: shaded → has hemophilia → genotype X^h Y
- Son #5: shaded → X^h Y
- Son #7: unshaded → X^H Y

Since sons #4 and #5 are affected (X^h Y), they got X^h from mom → so mom (#2) must be carrier → X^H X^h

Dad (#1) is unshaded male → must be X^H Y

Now daughter #3: she got X^H from dad (since dads give X to daughters), and from mom she could get X^H or X^h.

She is unshaded → so even if she got X^h, she’d be carrier but not sick.

But in the diagram, under #3 it says “X^H X^H” — which would mean she got X^H from both parents.

Is that possible? Yes — 50% chance.

Similarly, son #7 is unshaded → got Y from dad, and X^H from mom → so mom gave him X^H.

That’s consistent.

Now, #3 marries #4.

#4 is shaded male → X^h Y

#3 is unshaded female → if she is X^H X^H, then all her children:

Daughters: get X^H from mom, X^h from dad → X^H X^h → carriers, unshaded

Sons: get Y from dad, X^H from mom → X^H Y → unshaded

Which matches the next generation: individuals 9,10,11,12 — all unshaded circles/squares → so yes, makes sense.

If #3 were X^H X^h, then half her sons could be affected — but none are → so likely she is X^H X^H.

Similarly, #5 (affected male, X^h Y) marries #6 (unshaded female)

Their children: 13 and 14 — both unshaded.

Daughter 13: gets X^h from dad, and X^? from mom.

She is unshaded → so must have gotten X^H from mom → so mom (#6) must have at least one X^H.

Son 14: gets Y from dad, X^? from mom → unshaded → so got X^H from mom.

So #6 must be X^H X^H or X^H X^h — but since both kids are unaffected, and dad is X^h Y, the only way daughter is unaffected is if she got X^H from mom — which she did.

But we don’t know if #6 is homozygous or heterozygous — unless more info.

In the diagram, under #6 it says “X^H X^h” — so maybe that’s given? Or inferred?

Actually, if #6 were X^H X^H, then all children would be unaffected — which they are.

If she were X^H X^h, then 50% chance sons affected — but son 14 is unaffected — still possible.

But since no affected children, we can’t be sure — but perhaps in context, we assume minimal assumptions.

Wait — look at #7 and #8.

#7: unshaded male → X^H Y

#8: unshaded female → in diagram says “X^H X^H”

Their child: 15 — unshaded female.

Gets X^H from dad, and X^H from mom → X^H X^H — fine.

Now back to #6 — why is she labeled X^H X^h in the diagram?

Perhaps because if she were X^H X^H, then her daughter 13 would be X^H X^h (carrier), and son 14 X^H Y — both unaffected — same as if she were X^H X^h.

But if she were X^H X^h, then there’s a 50% chance son is affected — but he isn’t — so it’s possible she is X^H X^H.

However, in many such problems, if a woman has an affected brother or father, she might be carrier — but here, #6’s parents aren’t shown.

Actually, #6 is married to #5, who is affected — but that doesn’t affect her genotype.

Perhaps the diagram intends for us to use the labels given.

Looking back at your image description — under each person, the genotype is already written:

#1: X^H Y
#2: X^H X^h
#3: X^H X^H
#4: X^h Y
#5: X^h Y
#6: X^H X^h
#7: X^H Y
#8: X^H X^H

And then below, blurred text — probably questions like "What is the phenotype of individual 9?" etc.

Since the task is to "write in the genotypes", and they are already filled in the image, I think those are the correct answers.

To confirm:

- #1: unaffected male → X^H Y ✓
- #2: unaffected female with affected sons → must be carrier → X^H X^h ✓
- #3: unaffected female, daughter of #1 and #2; since she has no affected sons, and in diagram she’s X^H X^H — plausible ✓
- #4: affected male → X^h Y ✓
- #5: affected male → X^h Y ✓
- #6: unaffected female married to affected male; has unaffected children — could be X^H X^H or X^H X^h — but in diagram X^H X^h — perhaps to show she could be carrier, though not necessary. Maybe because if she were X^H X^H, her daughter 13 would be obligate carrier, but still unaffected. Actually, no issue. Perhaps it’s arbitrary, but since it’s given, we accept it.
- #7: unaffected male → X^H Y ✓
- #8: unaffected female → X^H X^H (as per diagram) ✓

All make sense.

So the genotypes are as labeled in the image.

Therefore, for the answer, since the question is to write the genotypes, and they are already provided correctly in the diagram, I will list them as such.

Final Answer:
#1: X^H Y
#2: X^H X^h
#3: X^H X^H
#4: X^h Y
#5: X^h Y
#6: X^H X^h
#7: X^H Y
#8: X^H X^H