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The Secrets of Bedrock

Sex-linked Traits with Fred and Wilma

Background

Geneticists have finally succeeded in sequencing the genes on the sex chromosomes of Bedrock’s most famous couple, Fred and Wilma Flintstone. Some shocking discoveries have been made and the secrets of Bedrock can now be revealed.

Traits on the X chromosome (in the order they appear from top to bottom)

|Dominant |Recessive |

|O – predisposed to obesity |o – not predisposed to obesity |

|C – Normal vision (can see red and green) |c – red-green colorblindness |

|B – Normal hair growth |b – baldness |

|H – Normal blood clotting |h- hemophilia (blood does not clot) |

|D – Normal hearing |d – deafness |

|P – Pigmented eyes (brown, blue, or green) |p – red eyes (no pigment) |

|E – Faulty tooth enamel |e – normal tooth enamel |

|S – Sweat glands present |s – sweat glands absent |

|M – Not predisposed to migraines |m – predisposition to migraines |

Trait on the Y chromosome

|Dominant |Recessive |

|H – hair growth in ears absent |h- hair growth in ears present |

1. Circle Wilma’s sex chromosome combination: XX or XY

2. Circle Fred’s sex chromosome combination. XX or XY

3. Complete the following table by filling in Fred and Wilma’s phenotypes for each genotype listed.

|Trait |Fred’s Phenotype |Fred’s Genotype |Wilma’s Phenotype |Wilma’s Genotype |

|Obesity |Obese |XOY |Not obese |XoXo |

|Color Vision | |XcY | |XCXc |

|Hair Growth | |XBY | |XbXb |

|Blood Clotting | |XHY | |XHXh |

|Hearing | |XDY | |XdXd |

|Eye Pigment | |XpY | |XPXp |

|Tooth Enamel | |XEY | |XeXe |

|Sweat Glands | |XsY | |XSXs |

|Migraines | |XmY | |XMXM |

| | | | | |

|Ear Hair | |XYh | |------ |

4. Can Wilma tell the difference between red and green Christmas lights? Explain

5. Does Wilma have faulty tooth enamel? Explain.

6. Do you think Wilma gets her hair done every week? Explain.

7. For which traits is Wilma a carrier? List them.

8. For which traits is Fred a carrier? List them.

9. Is Fred lying when he tells Wilma that her hair is a gorgeous shade of red? Explain.

10. A dedicated pet owner, Fred walks Dino once a day, but has a hard time cooling his body down Explain why this is true (hint: what feature helps people lose heat when they are exercising).

11. Does Fred need to wear a toupee (which is a wig for a man)? Explain.

12. Does Pebbles need to be treated for faulty tooth enamel? Set up a Punnett square to illustrate your answer. Answer yes or no and circle the possible genotypes of Pebbles in the Punnett Square.

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___________ (yes or no)

13. Does Pebbles wear a wig? Set up a Punnett square to illustrate your answer. Answer yes or no and circle the possible genotypes of Pebbles in the Punnett Square.

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___________ (yes or no)

14. What percent chance does Pebbles have to be predisposed to obesity? Show your work.

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Percent Chance =___________

15. If Fred and Wilma had a son, what are his chances of having normal vision? Show your work.

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Percent Chance=___________

16. Does Wilma get angry when Fred screams…”WILMAAAAAAAAAA”? Explain.

17. What chance does Pebbles have to develop hairy ears? Explain.

Part II: Family or Fraud?

The town of Bedrock is rocked to the core. A young man named “Fredrick” has just arrived in Bedrock, and he claims to be the son of one of the Flintstones!! Who fathered/mothered Fredrick? It’s up to you to solve this mystery. Fortunately Fredrick agreed to DNA sequencing and the results are now in.

Procedures:

Find the yellow chromosomes, which below to “Fredrick”. Fredrick’s X and Y chromosomes have already been sequenced and assembled.

Use Fredrick’s chromosomes to answer the following questions.

1. Fill in Fredrick’s phenotype for each sex-linked trait in the table below.

|Trait |Fredrick’s Genotype |Fredrick’s Phenotype |

|Obesity |XoY (little o) | |

|Color Vision |XcY (little c) | |

|Hair Growth |XbY | |

|Blood Clotting |XHY | |

|Hearing |XDY | |

|Eye Pigment |XpY(little p) | |

|Tooth Enamel |XeY | |

|Sweat Glands |XsY(little s) | |

|Migraines |XmY | |

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|Ear Hair |XYH | |

2. Which parent gave Frederick the X chromosome, mom or dad? _______________

3. Which parent gave Fredrick the Y chromosomes, mom or dad? _______________

4. Can Fred be the father of Fredrick and how do you know? Provide “genetic evidence” to support your answer. (Hint: look at the chromosome Fred had to have given to Frederick)

5. Can Wilma be Fredrick’s mother and how do you know? Provide “genetic evidence” to support your answer. (Hint: look at the chromosome Wilma had to have given to Frederick).

6. Why are males affected by recessive sex-linked diseases more often than females?

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