Download Pipe Cleaner Genetics

NAME _______________
Pipe Cleaner Genetics
The following human traits are carried by dominant alleles.
Widow’s peak – a hairline that forms a V-shape at the center of the forehead
Free earlobes – earlobes that hang below the point of attachment to the head
Dimples – indentations in the cheeks
Freckles – dark spots on the skin
Trait
Dominant allele
Recessive allele
Widow’s peak
W
w
Free earlobes
E
e
Dimples
D
d
Freckles
F
f
Procedure
1. Using three different colors of pipe cleaners, make three different
homologous pairs (Remember: That’s a total of six chromosomes!). Keep
in mind that a real human cell would have 23 homologous pairs (46 total
chromosomes), but we want to simplify things.
X
X
X
W
F
W
E
E
D
D
F
X
X
X
w
w
w
e
e
d
d
f
f
2. Pretend your table is a cell. Use your pipe cleaner chromosomes to model
the different phases of mitosis.
How many daughter cells did you make? _______
How many chromosomes does each daughter cell have? ______
Are the daughter cells diploid or haploid? _________
Are the genotypes of the daughter cells the same or different?
__________
3. Now use your pipe cleaner chromosomes to model the different phases of
meiosis.
How many daughter cells did you make? ___________
How many chromosomes does each daughter cell have?
___________
Are the daughter cells diploid or haploid? ___________
Are the genotypes of the daughter cells the same or different?
__________
Of the 4 genes, which gene(s) obeyed Mendel’s Law of
Independent Assortment?
Which gene(s) did NOT obey Mendel’s Law of Independent
Assortment? Why?
4. In step 6, you should have just made 4 gametes (sperm or eggs). Pick
another table that you would like to “mate” with. Choose one of your
gametes to be involved in fertilization. If you have sperm, then the one you
chose is the sperm cell that reached the egg and fertilized it first. If you
have eggs, then the egg you chose is the one that was ovulated this
month. Combine the chromosomes of your gamete with the chromosomes
of the other table’s gamete. You have just conceived a new child!
What is the genotype of your child (You should now have 4 pairs of
alleles, one pair for each trait)? _______________
What is the phenotype of your child (for each trait)?
5. In the space below, draw what the head of your child would look like as a
teenager. Your drawing should clearly demonstrate the phenotype of your
child.