Pipe Cleaner Babies Activity
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 chromosomes and gene models to create four
offspring and determine their genotypes and
phenotypes. Then, you will mathematically determine
the probability of having an 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, which contain thousands of genes. For this
exercise, we will only focus on a few.
Without opening the bag, notice that you have 4 white and 2 colored pipe cleaners. If you
have 2 red chromosomes, you are the female (XX). If you have 1 red and 1 green, you
are to play the male (XY).
1.
2.
3.
4.
5.
6.
What do the pipe cleaners represent (in general)?____________________________
What do the beads represent? ___________________________________________
What color is the X-chromosome?_________________________________________
What color is the Y-chromosome? _________________________________________
If you have 2 red chromosomes, what is your genotype? _______________________
If you have 1 red and 1 green chromosome, what is your genotype? _____________
Figure out the parents traits:
Remove the chromosomes from the bag, but make sure you do NOT mix up yours and your
partners chromosomes. Arrange the chromosomes in order of size. You should have 2
long white pipe cleaners, 2 short white pipe cleaners and 2 colored pipe cleaners.
The white chromosomes represent Autosomes.
The colored chromosomes represent Sex Chromosomes.
Eye Color (Long white chromosomes)
Hair Color (Short white chromosomes)
Orange bead = dominant – brown eyes
Red bead = dominant – dark hair
Blue bead = recessive – blue eyes
Yellow bead = recessive – blonde hair
BB = Brown; Bb = Brown; bb = blue
DD = Dark; Dd = Dark; dd = blonde
1.
2.
3.
4.
What color eyes does the mom have? _______
What color hair does mom have? ___________
What color eyes does the dad have? _______
What color hair does dad have? ___________
What is her genotype? ___________
What is her genotype? ___________
What is his genotype? ___________
What is his genotype? ___________
Hemophilia (Sex-Linked trait)
Purple bead = dominant gene – Normal;
Clear bead = recessive gene – Hemophiliac
Girls: XH XH = Normal; XH Xh = Normal (carrier); Xh Xh = hemophiliac
Boys: XHY = Normal; XhY = hemophiliac
1.
2.
3.
4.
What is mom’s genotype?________________ phenotype? ________________
Is mom a carrier? ____________
What is dad’s genotype? _________________ phenotype? ________________
Why doesn’t dad have 2 alleles for this trait? ________________________________
_____________________________________________________________________
Time to start your family
 Dad will place one set of homologous chromosomes behind his back, with a
chromosome in each hand. Mom will pick the hand she wants and that chromosome
will be passed to baby. Lay this chromosome on the table in front of you and set the
other aside.
 Repeat this procedure for the other homologous pairs.
 Now, mom places the 3 different sets of chromosomes behind her back and the dad
chooses.
 The chosen chromosomes are set on the table in front of you and are the genes for your
child.
Determine the traits of your child
Arrange the chromosomes into homologous pairs and determine the genotypes and
phenotypes of baby #1.
Data
Child
#
Sex
Eye color
phenotype
Eye color
genotype
Hair color
phenotype
Hair color
genotype
Hemophilia Hemophilia
phenotype genotype
1
2
3
4
Analysis
1. Create a punnett square for each of the crosses, using your parents. (you will have a
separate square for hair color, eye color, hemophilia and sex). Determine the
percent chance of obtaining a child with each genotype and phenotype represented
– for each trait.
2. Explain why women are carrier’s for the disease hemophilia. Why do their son’s get
the disease, but not necessarily the daughters?
3. Describe the difference in the inheritance of autosomal traits and sex-linked traits.
4. If you knew you were a carrier for hemophilia (or your husband/wife was), would
you choose to have children? Explain your answer.