Name: __________________________
Pipe Cleaner Babies
In this activity you will play the role of a parent, your lab partner will play the role of the other parent. You will use chromosome
and gene models to create an offspring. You will then use class data to determine how accurate Punnett squares are by
comparing probability to what is actually seen in a population.
Step 1: How to Use the Model:
You will receive a baggie with pipe cleaners and beads. The pipe cleaners represent chromosomes and the beads represent
genes located on the chromosomes. In humans, there are 23 pairs of chromosomes, 23 from their mom and 23 from their dad.
This means that humans have a total of 46 chromosomes in each of their cells. Humans have thousands of different genes, but
for this exercise, we will only focus on a few. When you get your bag, you will notice that you have four white and two colored
pipe cleaners. If you have two pink chromosomes, you are to play the role of female (XX). If you have one pink and one blue,
you are to play the role of the male (XY).
You will not earn your chromosomes until you answer the following questions and show the teacher.
1. What do the pipe cleaners represent? ___________________________________
2. What do the beads represent? ______________________
3.
4.
Humans have ___________ pairs of chromosomes. How many is that total? ___________
If you have two pink pipe cleaners, you are playing the role of _________________
5. If you are the mom what is your genotype? _______
6. If you have a pink and a blue pip cleaner, you are playing the role of _________________
7. If you are the dad what is your genotype? _______
8. The blue pipe cleaner represents the _________ chromosome.
Before you start, please make sure that you have the correct combination of pipe cleaners in your bag!!!!
This is what you should see:
Step 2: Figure out the parents traits:
Remove the chromosomes from the bag, but make sure you do NOT mix up you and your partner's
chromosomes!!! Arrange the chromosomes in order of size, you should have:
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Two long white pipe cleaners
Two shorter pipe cleaners
Two colored pipe cleaners.
The white pairs represent HOMOLOGOUS CHROMOSOMES.
9. What are homologous chromosomes? (look it up!)
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The colored pairs represent SEX CHROMOSOMES
10. What are sex chromosomes? (look it up!)
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HOMOLOGOUS CHROMOSOMES
Eye Color
Hair Color
(longer white pipe cleaners)
(shorter white pipe cleaners)
Brown/Orange bead represents the dominant gene (B) - brown
Blue bead represents the recessive gene (b) - blue
Red bead represents the dominant gene (D)- dark
White bead represents the recessive gene (d) - blonde
BB = brown eyes | Bb = brown eyes | bb = blue eyes
DD= dark hair | Dd = dark hair | dd = blonde hair
What is her genotype? ___ ___ (what color beads?)
What is her phenotype? What color eyes? _____________
What is her genotype? ___ ____ (what color beads?)
What is her phenotype? What color hair? _____________
What is his genotype? ____ ____(what color beads?)
What is his phenotype? What color eyes? _____________
What is his genotype? ____ ____(what color beads?)
What is his phenotype? What color hair? _____________
What is the probability
for each eye color in
their offspring?
What is the probability
for each hair color in
their offspring?
Brown? = _______%
Dark? = _______%
Blue? = ________%
Blonde? = ________%
SEX CHROMOSOMES
Hemophilia
(colored pipe cleaners)
Purple bead represents the dominant gene (H) -- normal
Clear bead represents the recessive gene (h) – hemophiliac
X__
**In girls**
XHXH = normal | XHXh = normal (carrier) | XhXh = hemophiliac
**In boys**
XHY = normal | XhY = hemophiliac
What is mom's genotype? ___ ___
What is mom’s phenotype (Is she a carrier?) ___________
Y__
X__
X__
What is dad's genotype? ___ ___
What is dad’s phenotype (Is he a carrier?) __________
Why doesn't dad get two alleles for this trait?
________________________________________________________
________________________________________________________
_______________________________________________________
Because this is a sex linked trait,
the Punnett square is going to
look a little different!
Step 3: Time to Start Your Family
1. The dad places one set of the homologous pairs of chromosomes (longer set of pipe cleaners) behind
his back, with a chromosome (pipe cleaner) in each hand. The mom picks the hand she wants for the
child. Lay this chromosome on the table in front of you and set the other aside (out of the way).
2. Repeat this procedure for the other homologous pair (shorter set) and for the sex chromosomes
(colored set). **It’s should be noted that if the blue chromosome gets chosen from the sex chromosomes, the child
in this cross is going to be a boy.
3. Now the mom does the same process. “She” can start by placing one set of the homologous pairs
behind her back and the male chooses, and then repeat with the remaining chromosome pairs.
4. The chromosomes chosen and set on the table in front of you are the genes your first child will receive!
Step 4: Determine the Traits of Your First Child
Arrange the chromosomes into homologous pairs (2 long, 2 short, 2 colored) and figure out what
phenotypes (appearance or observable trait) the offspring has.
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What is the child’s genotype for gender? ___ ___ Phenotype? _______________
What is the child’s genotype for eye color? ___ ___ Phenotype?______________
What is the child’s genotype for hair color? ___ ___ Phenotype?_____________
Is the child’s genotype for hemophilia? ___ ___ Phenotype? ________________
Step 5: Data Table
(Hemophiliac, Normal, or Carrier)
Go to the last page for the class data table, your group is group # _______ .
When you are finished, you will post your data on the board. Other groups will also post their children's
data. Fill out the entire chart to find out the traits of the new generation of children.
**Please make sure you have the right chromosomes in the right bags when you return them!!
Individual Group Data
Eye Color
Hair Color
Sex
Hemophilia
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 8
Group 9
Group 10
Group 11
Group 12
Group 13
Group 14
Group 15
Group 16
Complete Class Data
# of
Babies
with trait
Total Number of Babies
Total Number of Girls
Total Number of Boys
# of Babies with Brown Eyes
# of Babies with Blue Eyes
# of Babies with Dark Hair
# of Babies with Blonde Hair
# of Girls with Hemophilia
# of Boys with Hemophilia
Percentages
Step 6: Analysis
Directions: Using the class data, answer the following and use full and complete sentences.
1. Explain why women are carriers for the disease hemophilia. Why do their sons, but not their
daughters get the disease?
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2. Describe the difference between how normal traits are inherited and how sex linked traits are
inherited.
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3. The information on the data table collected by the class shows how many ACTUAL offspring would
have each of the traits.
The Punnett squares you completed on page 2, show the PREDICTED ratios.
Compare the predicted ratios to the actual results for all three traits.
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4. Notice on the data table that no female has the disease hemophilia. Explain why.
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5. If you knew you were a carrier for hemophilia (or your wife was), would you choose to have children.
Explain your reasons.
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