Name: ________________________________________________ Period: ___________

 

The Secrets of Bedrock

 

Sex-linked Traits

With Fred & 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!

 

Materials

 

  1. Blue shapes identifying the genes on Fred’s X and Y chromosomes.
  2. Pink shapes identifying the genes on Wilma’s two X chromosomes.

 

Procedure

 

  1. Assemble the pink shapes like puzzle pieces into Wilma’s two X chromosomes. Each chromosome should consist of 7 genes. When the chromosomes are assembled, align the chromosomes next to each other as homologous pairs. (HINT: the completed chromosomes will not be shaped like an X or Y but should be rectangular with smooth edges.)
  2. Assemble the blue shapes like puzzle pieces into Fred’s X and Y chromosomes. The Y chromosome is composed of only one gene with thick black edges.
  3. Write the genotypes in Table 1.

 

 

 

 

 

 

 

Analysis

 

Use your assembled chromosomes to complete table 1. Use the information in the tables below to answer the questions in the spaces provides.

 

Table 1:

Trait

Wilma’s Genotype

Fred’s Genotype

blood clotting

XHXh

XHY

vision

XBXb

XBY

muscular dystrophy

XMXm

XMY

hair growth

XnXn

XNY

sweat glands

XGXg

XgY

tooth enamel

XeXe

XEY

ALD

XAXa

XAY

hair growth in ears

XX

XYt

 

 

Traits on the X chromosome

 

Dominant

Recessive

H – normal blood clotting

h – hemophilia (blood does not clot)

B – normal vision

b – red-green color blindness

M – no muscular dystrophy

m – muscular dystrophy

N -  normal hair growth

n – baldness

G – sweat glands present

g – sweat glands absent

E – faulty tooth enamel

e – normal tooth enamel

A – no ALD

a - ALD

 

Traits on the Y chromosome

 

Dominant

Recessive

T – hair growth in ears absent

t – hair growth in ears present

 

1.      Which color of shapes represents Wilma’s sex chromosomes? _____________

 

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

 

 

3.      Which color of shapes represents Fred’s sex chromosomes? ______________

 

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

 

 

5.      What is Wilma’s genotype for the trait hemophilia vs normal blood? __________________________________

 

6.      What is Wilma’s genotype for the trait color blindness vs normal vision? __________________________________

 

7.      Can Wilma tell the difference between red and green Christmas lights? Explain why or why not?

 

 

 

8.      What is Wilma’s genotype for the trait faulty vs normal tooth enamel? ___________________________________

 

9.      Does Wilma have faulty tooth enamel? Explain why or why not?

 

 

 

10.  What is Wilma’s genotype for the trait baldness vs normal hair? ___________________________________

 

 

11.  Do you think Wilma gets her hair done every week? Explain why or why not?

 

 

 

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

 

 

 

 

 

13.  What is Fred’s genotype for the trait color blindness vs normal vision? ____________________________________

 

14.  Is Fred lying when he comments on Wilma’s gorgeous red hair? Explain why or why not in terms of Fred’s vision.

 

 

15.  What is Fred’s genotype for the trait of sweat glands being present or absent? ____________________________________

 

16.  A dedicated pet owner, Fred walks Dino once a day but has a hard time keeping himself cool. Explain why.

 

17.  What is Fred’s genotype for the trait baldness vs normal hair? ___________________________________

 

18.  Does Fred need to wear a toupee? Explain why or why not.

 

 

 

19.  If Fred and Wilma had two children, a boy and a girl (Pebbles), would the kids have to be treated for faulty tooth enamel? Set up a Punnett square to illustrate your answer. Explain your answer.

 

 

 

 

 

 

 

 

20.  What is the probability of Fred and Wilma’s daughter Pebbles having muscular dystrophy? Set up a Punnett square to illustrate your answer. Give your answer as a percentage. Explain your answer.

 

 

 

 

 

 

 

 

 

21.  Could Fred and Wilma have a son who would go bald? Set up a Punnett square to illustrate your answer. Explain your answer.

 

 

 

 

 

 

 

 

22.  If Fred and Wilma had a son, what would be the probability of him being able to sweat normally? Set up a Punnett square to illustrate your answer. Explain your answer.

 

 

 

 

 

 

 

 

23.  Why are more males affected by sex-linked traits than females?