Name ________________________________________________________Period____ Date _______
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 – not predisposed to obesity
O – 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
H – hair growth in ears absent
Recessive
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
Obesity
Fred’s Phenotype
Fred’s Genotype
Wilma’s
Phenotype
Wilma’s
Genotype
Obese
XOY
X cY
XBY
X HY
XDY
XpY
XEY
XsY
XmY
Not obese
XX
C c
XX
b b
XX
H h
XX
d d
XX
P p
XX
e e
XX
S s
XX
M M
X X
Color Vision
Hair Growth
Blood
Clotting
Hearing
Eye Pigment
Tooth Enamel
Sweat Glands
Migraines
Ear Hair
XYh
o
o
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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.
___________ (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.
___________ (yes or no)
14. What percent chance does Pebbles have to be predisposed to obesity? Show your work.
Percent Chance =___________
15. If Fred and Wilma had a son, what are his chances of having normal vision? Show your work.
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
o
Color Vision
Hair Growth
Blood Clotting
Hearing
Eye Pigment
Tooth Enamel
Sweat Glands
Migraines
Ear Hair
X Y (little o)
XcY (little c)
XbY
XHY
X DY
XpY(little p)
X eY
XsY(little s)
XmY
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?