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genetics

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Genetics with a SMILE!!
Part A:

Name: __________________________________
Smiley Face Traits
Obtain two coins from your teacher. Mark one coin with an “F” and the other with an “M” to
represent each of the parents for your Smiley. The parents are heterozygous for all of the Smiley Face
traits (except for blood type).

Flip the coins for each trait to determine which alleles get passed onto the offspring. The columns are
labeled for ‘Heads up’ and ‘Tails up’. Write the letter for each allele from the coin toss in the
‘Genotype’ column to form your Smiley’s genotype.

Use the ‘Smiley Face Traits’ page to determine the phenotype for your Smiley.
Female
Male
Trait
Heads up
Tails up
Heads up
Tails up
Face shape
C
c
C
c
Eye shape
E
e
E
e
Hair style
S
s
S
s
Smile
T
t
T
t
Ear style
V
v
V
v
Nose style
D
d
D
d
Face color
Y
y
Y
y
Eye color
B
b
B
b
Hair length
HL
HS
HL
HS
Freckles
F
f
F
f
Nose color
R
Y
R
Y
Ear color
P
T
P
T
Gender
X
X
X
Y
Blood type
IA
i
IB
i
Color-blindness
XN
Xn
Xn
Y
Genotype
Phenotype
Part B:

Create your Smiley!
Use the ‘Smiley Face Traits’ page and your results from Part A
to create a sketch of your Smiley in the box to the right.

Once you have completed the sketch, use the drawing tools
in Microsoft Word or Paint to create your Smiley!

On your finished document, be sure to give your Smiley a
name and include your name and class period as well.

DO NOT PRINT until you are given the OK from your teacher.
Part C:
Analyzing Results
Answer the following questions about your Smiley in the space provided. Be sure that your answers are
complete and fully answer the question that is being asked.
1. Overall, does your Smiley have more dominant traits or recessive traits expressed?
2. Which trait(s) is a result of codominance? How is this expressed in a heterozygous offspring
(phenotype)?
3. Which trait(s) is a result of incomplete dominance? How is this expressed in a heterozygous offspring
(phenotype)?
4. Which trait(s) is a result of multiple alleles? What kind of interaction is there between the multiple
alleles (dominant/recessive, codominance, incomplete, etc.)?
5. Which trait(s) is a result of a sex-linked gene? How do you know?
6. How would your Smiley change if ONE of the parents were homozygous dominant for all the traits
while the other was heterozygous?
7. Uncle Smiley, who is heterozygous for a yellow face, married a woman with a green face. Both of
them have always wanted a large family! If they were to have 12 children, what is the probability that
the children would have yellow faces? What is the probability they would have green faces? Create a
Punnett square to help show your answers.
8. Grandmas and Grandpa Smiley are heterozygous for the star eye shape. If one of their homozygous
children married a girl with blast-type eyes, what percentage of their grandchildren might have starry
eyes? What percentage might have blast-type eyes? Create a Punnett square to help show your
answers.
9. Baby Smiley has curly hair, but neither of her parents do!! Is this possible? Create a Punnett square to
help show your answers.
10. Both Aunt and Uncle Smiley have Type B blood. Is it possible for them to have a baby Smiley with Type
O blood? Is it possible for them to have a baby Smiley with Type A or Type AB blood? Create a
Punnett square to help show your answers.
Part D:
Extension
What if we wanted to look at the probability of getting an offspring with TWO specific traits!! We can still
create a Punnett square to show the possible outcomes, but it would require more boxes. First, we have to
find all the possible TWO allele combinations for each parent and then create a row/column for each. If we
are dealing with TWO traits, we could need 16 boxes! The probability is still expressed the same (as ____ out
of _____) and a percent can then be calculated. Use the information below to complete the Punnett square
for TWO traits and answer the questions that follow.
Mr. Smiley is heterozygous for both nose style (Dd) and freckles (Ff). So is Mrs. Smiley!
Mr. Smiley – DdFf
Mrs. Smiley - DdFf
DF
DF
Df
dF
df
DDFF
Complete the Punnett square as you normally
would, just be sure to place the same letters
Df
DdFf
next to one another. A few examples have
been completed for you.
dF
df
ddFf
Ddff
What is the probability of producing a baby Smiley with the following traits:
a) a down nose and freckles -
________ out of a possible __________
OR
______________ %
b) a down nose and NO freckles -
________ out of a possible __________
OR
______________ %
c) an up nose and freckles -
________ out of a possible __________
OR
______________ %
d) an up nose and NO freckles -
________ out of a possible __________
OR
______________ %
Smiley Face Traits
Face Shape
Circle (C)
Nose Style
Square (c)
Down (D)
Up (d)
Eye Shape
Star (E)
Blast (e)
Hair Style
Straight (S)
Curly (s)
Smile
Thick (T)
Thin (t)
Ear Style
Curved (V)
Pointed (v)
Face Color
Yellow (Y)
Green (y)
Eye Color
Blue (B)
Red (b)
Hair Length
Long (HL)
Short (HS)
BOTH long/short (HLHS)
Nose Color
Red (R)
Yellow (Y)
Orange (RY)
Freckles
Present (F)
Absent (f)
Ear Color
Hot Pink (P)
Teal (T)
Purple (PT)
Gender
Female (XX) – pink bow in hair
Male (XY) – blue bow in hair
Color Blindness
Normal vision (N) – NO glasses
Colorblind (n) – ADD glasses
Blood Type
Type A (IA)
Type B (IB)
Type O (i)
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