Teacher notes and Prep materials

Parents_______________________ _______________________

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 four offspring and determine their genotypes and phenotypes. Then mathematically, you will determine the probability of having offspring with different traits.

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 and thousands of genes, but for this exercise, we will only focus on a few. 

Without opening the bag, 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).  

1.  What do the pipe cleaners represent?   ____________________

2.  What do the beads represent?   __________________

3.  Humans have  ___________  pairs of chromosomes.

4.  If you have two pink pipecleaners, you are playing the role of  ___________

5.  The blue pipecleaner represents the  _______  chromosome.

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 two long white pipecleaners, two shorter pipecleaners, and the two colored pipecleaners.

The white pairs represent HOMOLOGOUS CHROMOSOMES. 

The colored pairs represent SEX CHROMOSOMES

Eye Color  (longer white pipe cleaners)

Grey bead represents the dominant gene  ---  brown eyes

Blue bead represents the recessive gene  --- blue eyes

BB  = brown eyes                  Bb =  brown eyes                  bb = blue eyes

What color eyes does the “mom”  have?   ______    What is her genotype?  ____

What color eyes does the “dad” have?   _____   What is his genotype?    _____

Hair Color (shorter white pipe cleaners)

The red bead represents the dominant gene  -- dark hair

The ivory bead represents the recessive gene ­ blonde hair

DD  = dark hair          Dd = dark hair                       dd = blonde hair

What color hair does “mom” have ?  _______   What is her genotype?  ______

What color hair does “dad” have?   ________   What is his genotype?    ______

Hemophilia (sex chromosomes, colored pipe cleaners)

The purple bead represents the dominant gene  --  normal

The clear bead represents the recessive gene  --  hemophiliac

In girls:  HH =  normal            Hh = normal (carrier)             hh  =  hemophiliac

In boys:     H  = normal          h  = hemophiliac

What is “mom’s”   genotype?   __________     Is she a carrier?   _________

What is “dad’s”  genotype?    ___________

Why doesn’t dad get two alleles for this trait?     _______________________

Time to Start Your Family

--The “dad” places one set of the homologous pairs (ex: that longer set) behind his back, with a chromosome 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.

-- Repeat this procedure for the other homologous pair (ex: shorter set) and for the sex chromosomes.  Its 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.

--Now the “mom” places one set of the homologous pairs behind her back and the male chooses.   

-- The chromosomes chosen and set on the table in front of you are the genes your first child received.

Determine the Traits of Your First Child

Arrange the chromosomes into homologous pairs and figure out what phenotypes (appearance or trait) the offspring has.

What is the sex of the child?   _________

What color eyes does the child have?  _______   Genotype?  ______

What color hair does the child have?   _______  Genotype?   ________

Is the child a hemophiliac? ______   Is the child a carrier for hemophilia? _____

Data  Table

Go to the last page and see the data table, the first group is you and your partner.  You  are going to have 4 children.   Repeat the procedure you used to make you first child to make 3 others.  Fill out their traits on the table.

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 will all the parents in the class.

Replace all Chromosome into the Correct Baggie

Make sure you have the right chromosomes in the bag and return.

 

 

Analysis

---On a separate page, answer the following.  Each person in the group must fill out their own analysis section.

1.  Create a punnet square for each of the crosses, using your parents.  (You’ll have a square for hair color, eye color, and hemophilia)

2.  Explain why women are carrier’s for the disease hemophilia.  Why do their sons, but not their daughters get the disease?

3.  Describe the difference between how normal traits are inherited and how sex linked traits are inherited.

4.  The data table where all the data is combined, shows how many ACTUAL offspring would have each of the traits.   The punnet squares (from #1) show the PREDICTED ratios.  Compare the actual to predicted ratios for all three traits.

5.  Notice on the data table that no female has the disease hemophilia.  Explain why.

6.  If you knew you were a carrier for hemophilia (or your wife was), would you choose to have children.   Explain your reasons.

**Turn in these pages (with both names), the data table,  and the answers to analysis (which should have a single name)

	Eye color	Hair Color	Hemophilia	Sex	Compile Data Total number of babies? _______ Number of girls? _____ Number of boys?  _____ Number of children with brown eyes _______ Number of children with blue eyes _______ Number of children with dark hair ________ Number of children with blonde hair  ______ Number of girls with hemophilia  _______ Number of boys with hemophilia  _______ Convert your data to percentages.  To get the percents, divide the number you have by the total number and x 100. Girls                         ______% Boys                       ______% Brown eyes           ______% Blue eyes               ______% Dark hair                ______% Blonde hair              ______% Hemophiliac boys  ______% Hemophilac girls    ______%
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 8
Group 9
Group 10
Group 11

If you need to add more data, continue the table on the back.