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Step-by-step solution for: Solved BIOLOGY URGENT, I WILL MAKE SURE TO UPVOTE Fill out | Chegg.com
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Show Answer Key & Explanations
Step-by-step solution for: Solved BIOLOGY URGENT, I WILL MAKE SURE TO UPVOTE Fill out | Chegg.com
Let's solve each scenario step by step using X-linked inheritance, where the gene for color vision is located on the X chromosome.
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- Colorblind allele = Xᶜ
- Normal vision allele = X^C
> Note: In genetics, we use X^c for colorblind (recessive) and X^C for normal vision (dominant). Since it’s X-linked, males have one X (from mother), and females have two X chromosomes.
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## ✔ Scenario 1: Colorblind Man × Woman with Normal Vision
- Man: Colorblind → Genotype: X^c Y
- Woman: Non-carrier, normal vision → Genotype: X^C X^C
| | X^C | X^C |
|-------|---------|---------|
| X^c | X^c X^C | X^c X^C |
| Y | X^C Y | X^C Y |
> So the offspring are:
- Daughters: All X^c X^C → carriers, but normal vision
- Sons: All X^C Y → normal vision
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1. Phenotype: Colorblind
2. Genotype: X^c Y
3. Allele(s): X^c, Y
4. Phenotype: Normal vision
5. Genotype: X^C X^C
6. Allele(s): X^C, X^C
7. Punnett Square (as above)
8. The baby boy has a 0% chance of being colorblind.
> Because all sons get X^C from mother → normal vision.
9. The baby girl has a 0% chance of being colorblind and 100% chance of being a carrier.
> All daughters inherit X^c from father and X^C from mother → X^c X^C → carrier, normal vision.
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## ✔ Scenario 2: Colorblind Woman × Man with Normal Vision
- Woman: Colorblind → Genotype: X^c X^c
- Man: Normal vision → Genotype: X^C Y
| | X^c | X^c |
|-------|---------|---------|
| X^C | X^C X^c | X^C X^c |
| Y | X^c Y | X^c Y |
> Offspring:
- Daughters: All X^C X^c → carriers, normal vision
- Sons: All X^c Y → colorblind
---
10. Phenotype: Normal vision
11. Genotype: X^C Y
12. Allele(s): X^C, Y
13. Phenotype: Colorblind
14. Genotype: X^c X^c
15. Allele(s): X^c, X^c
16. Punnett Square (as above)
17. If they have a daughter, what are the chances she will be colorblind?
→ 0%
> She will be X^C X^c → carrier, but since X^C is dominant, she has normal vision.
18. If they have a son, what are the chances he will be colorblind?
→ 100%
> He gets X^c from mother and Y from father → X^c Y → colorblind.
---
## ✔ Scenario 3: Colorblind Man × Carrier Woman
- Man: Colorblind → Genotype: X^c Y
- Woman: Carrier → Genotype: X^C X^c
| | X^C | X^c |
|-------|---------|---------|
| X^c | X^c X^C | X^c X^c |
| Y | X^C Y | X^c Y |
> Offspring:
- Daughters:
- 50% X^c X^C → carrier, normal vision
- 50% X^c X^c → colorblind
- Sons:
- 50% X^C Y → normal vision
- 50% X^c Y → colorblind
---
19. Phenotype: Colorblind
20. Genotype: X^c Y
21. Allele(s): X^c, Y
22. Phenotype: Carrier with normal vision
23. Genotype: X^C X^c
24. Allele(s): X^C, X^c
25. Punnett Square (as above)
26. If they have a daughter, what are the chances she will be colorblind?
→ 50%
> Because she can get either X^C or X^c from mother, and X^c from father → if she gets X^c from mom → X^c X^c → colorblind.
27. If they have a son, what are the chances he will be colorblind?
→ 50%
> He gets Y from father and X from mother. Mother gives X^c (50%) or X^C (50%). So 50% chance of X^c Y → colorblind.
---
| Scenario | Male Parent | Female Parent | Daughter Colorblind? | Son Colorblind? |
|--------|-------------|----------------|------------------------|------------------|
| 1 | X^c Y | X^C X^C | 0% | 0% |
| 2 | X^C Y | X^c X^c | 0% | 100% |
| 3 | X^c Y | X^C X^c | 50% | 50% |
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- Males are more likely to be affected because they only have one X.
- Females need two recessive alleles (X^c X^c) to be colorblind.
- A carrier female (X^C X^c) has normal vision but can pass the allele to children.
Let me know if you'd like this formatted as a printable answer sheet!
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🔹 Allele Notation Key:
- Colorblind allele = Xᶜ
- Normal vision allele = X^C
> Note: In genetics, we use X^c for colorblind (recessive) and X^C for normal vision (dominant). Since it’s X-linked, males have one X (from mother), and females have two X chromosomes.
---
## ✔ Scenario 1: Colorblind Man × Woman with Normal Vision
Given:
- Man: Colorblind → Genotype: X^c Y
- Woman: Non-carrier, normal vision → Genotype: X^C X^C
Step 1: Fill in the Punnett Square
| | X^C | X^C |
|-------|---------|---------|
| X^c | X^c X^C | X^c X^C |
| Y | X^C Y | X^C Y |
> So the offspring are:
- Daughters: All X^c X^C → carriers, but normal vision
- Sons: All X^C Y → normal vision
---
Answers:
1. Phenotype: Colorblind
2. Genotype: X^c Y
3. Allele(s): X^c, Y
4. Phenotype: Normal vision
5. Genotype: X^C X^C
6. Allele(s): X^C, X^C
7. Punnett Square (as above)
8. The baby boy has a 0% chance of being colorblind.
> Because all sons get X^C from mother → normal vision.
9. The baby girl has a 0% chance of being colorblind and 100% chance of being a carrier.
> All daughters inherit X^c from father and X^C from mother → X^c X^C → carrier, normal vision.
---
## ✔ Scenario 2: Colorblind Woman × Man with Normal Vision
Given:
- Woman: Colorblind → Genotype: X^c X^c
- Man: Normal vision → Genotype: X^C Y
Step 1: Punnett Square
| | X^c | X^c |
|-------|---------|---------|
| X^C | X^C X^c | X^C X^c |
| Y | X^c Y | X^c Y |
> Offspring:
- Daughters: All X^C X^c → carriers, normal vision
- Sons: All X^c Y → colorblind
---
Answers:
10. Phenotype: Normal vision
11. Genotype: X^C Y
12. Allele(s): X^C, Y
13. Phenotype: Colorblind
14. Genotype: X^c X^c
15. Allele(s): X^c, X^c
16. Punnett Square (as above)
17. If they have a daughter, what are the chances she will be colorblind?
→ 0%
> She will be X^C X^c → carrier, but since X^C is dominant, she has normal vision.
18. If they have a son, what are the chances he will be colorblind?
→ 100%
> He gets X^c from mother and Y from father → X^c Y → colorblind.
---
## ✔ Scenario 3: Colorblind Man × Carrier Woman
Given:
- Man: Colorblind → Genotype: X^c Y
- Woman: Carrier → Genotype: X^C X^c
Step 1: Punnett Square
| | X^C | X^c |
|-------|---------|---------|
| X^c | X^c X^C | X^c X^c |
| Y | X^C Y | X^c Y |
> Offspring:
- Daughters:
- 50% X^c X^C → carrier, normal vision
- 50% X^c X^c → colorblind
- Sons:
- 50% X^C Y → normal vision
- 50% X^c Y → colorblind
---
Answers:
19. Phenotype: Colorblind
20. Genotype: X^c Y
21. Allele(s): X^c, Y
22. Phenotype: Carrier with normal vision
23. Genotype: X^C X^c
24. Allele(s): X^C, X^c
25. Punnett Square (as above)
26. If they have a daughter, what are the chances she will be colorblind?
→ 50%
> Because she can get either X^C or X^c from mother, and X^c from father → if she gets X^c from mom → X^c X^c → colorblind.
27. If they have a son, what are the chances he will be colorblind?
→ 50%
> He gets Y from father and X from mother. Mother gives X^c (50%) or X^C (50%). So 50% chance of X^c Y → colorblind.
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✔ Final Summary Table:
| Scenario | Male Parent | Female Parent | Daughter Colorblind? | Son Colorblind? |
|--------|-------------|----------------|------------------------|------------------|
| 1 | X^c Y | X^C X^C | 0% | 0% |
| 2 | X^C Y | X^c X^c | 0% | 100% |
| 3 | X^c Y | X^C X^c | 50% | 50% |
---
📌 Key Takeaways:
- Males are more likely to be affected because they only have one X.
- Females need two recessive alleles (X^c X^c) to be colorblind.
- A carrier female (X^C X^c) has normal vision but can pass the allele to children.
Let me know if you'd like this formatted as a printable answer sheet!
Parent Tip: Review the logic above to help your child master the concept of sex linked punnett square worksheet.