 Smiley Face Genetics  (14 pts)
Purpose: To distinguish between dominant and recessive traits and make predictions about possible outcomes
of various genetic combinations of inherited characteristics.
Procedure:
Part A: Making a Baby!
(1) Obtain two coins from your teacher. Mark one coin with a “F” and the other with a “M” to represent each
of the parents. The parents are heterozygous for all the Smiley Face traits.
(2) Flip the coins for parent for each trait.
If the coin lands with heads up, it represents a dominant allele.
If the coin lands with tails up, it represents a recessive allele.
(3)Record the result for each person by circling the correct letter.
(4)Use the results and the Smiley Face Traits page to determine the genotype and phenotype for each trait.
Trait
Mom
Baby’s
Genotype
Dad
Face Shape
C
c
C
c
Eye Shape
E
e
E
e
Hair Style
H
h
H
h
Smile
T
t
T
t
Ear Style
A
a
A
a
Nose Style
D
d
D
d
Eye Color
B
b
B
b
Baby’s
Phenotype
Part B: Is it a boy or girl?
(1) The baby’s gender is always determined by the father. The mom is composed of only XX, which is
female. Males are XY. So, the father could give his offspring an “X” or “Y” chromosome.
Flip a coin for the dad to determine which gender chromosome he would pass on to the baby.
Heads would represent X, while tails would be Y.
Trait
Mom
Gender
X
Dad
X
Y
Baby’s
Genotype
Baby’s
Phenotype
Part C: Create your Smiley Face
Use the chart below and your results from Part A to create a smiley face. Don’t forget to give your
smiley face a name!
Trait
Face
Shape
Dominate
C—circle
Recessive
c—heart
Trait
Ear Style
Dominate
A—Curved
Recessive
a—Rectangle
Eye
Shape
E—plus signs
e—diamonds
Nose Style
D—triangle
d—oval
Hair
Style
H—straight
h—curly
Eye Color
B—orange
b—purple
Smile
T—thick
t—thin
Gender
XX-female
Add a pink bow
XY—male
Add a blue bow
Draw your smiley face on a separate piece of white paper. Be sure to give your smiley a name!
Reflection Questions:
Use complete sentences to answer the following questions.
(1) Why did you have to flip a coin to determine which allele each parent would pass on to the offspring? __
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(2) Why did you only have to flip the father’s coin to determine the gender of the offspring? _____________
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(3) If you were to do this again, would your offspring be exactly alike? _______________________________
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(4) How does this explain why siblings with the same parents can look very different or they can look very
similar? ______________________________________________________________________________
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