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Name:_______________________________________ Block: _________ Date:_________________
Genetics of Parenthood
Introduction:
Why do people, even closely related people look slightly different from each other? The
reason for these differences in physical characteristics, or phenotypes, is the different
combination of genes possessed by each individual. To illustrate the tremendous
variety possible when you begin to combine genes, you and a classmate will create a
potential offspring. Your offspring will receive a random combinations of genes that
each of you, as genetic partners, will contribute. Because we do not know your real
genotype, we are going to use specific traits and a coin to create the offspring. In this
lab, there are quite a few gene pairs and traits, but in reality there are thousands of
different gene pairs and so there are millions of different possible gene combinations.
Objective:
Create an offspring to observe the possible combinations of specific gene pairs.
Materials:
2 coins, 1 for each partner
reference sheets
colored pencils
Pre-lab Questions
1. In this situation, what does a single side of the coin represent? ______________________
_____________________________________________________________________________________
2. What is the probability, in percent, that a single coin toss will result in heads?
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3. Why is a coin toss a good way to represent allele combinations that occur in nature?
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4. Can you accurately determine an organism’s genotype by observing its phenotype?
Explain. _____________________________________________________________________________
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Procedure:
1. Determine which partner will toss for female and which will toss for male.
2. Discover your offspring’s gender. (XX- girl, XY- boy) This is entirely determined by the
father. The mother always contributes an X. So, only have the father toss his coin and
record on data sheet.
Heads: X chromosome, so the child is a girl
Tails: Y chromosomes, so the child is a boy
3. Name the offspring and record on data sheet.
4. Determine the child’s facial characteristics by having each parent flip a coin for
each trait.
Heads: offspring will inherit dominant allele or 1st allele (N1)
Tails: offspring will inherit recessive or 2nd allele (N2)
On the data sheet, circle the allele that the parent will pass on to the child and write
the child’s genotype.
 Use the information in the guide to refer to the offspring’s phenotype.
 Some traits may have special conditions, such as incomplete dominance or
polygenic traits. Be sure to refer to trait before flipping the coin.
5. When data sheet is complete, draw your “bundle of joy” with all of the traits you
determined by the coin toss OR create an image of your offspring in “Paint” on the
computer.
Genetics of Parenthood Data Table:
Parents: ___________________________________and __________________________________
Child’s gender:_____________________ Child’s Name:_______________________________
#
Trait
1
2
3
4
5
Face Shape
Chin Size
Chin Shape
Cleft Chin
Skin color
6
Hair color
7
8
Hair type
Widow’s Peak
9
Eye color
10
11
12
13
Eye distance
Eye size
Eye shape
Eye slantedness
14
15
Eyelashes
Eyebrow thickness
16
Eyebrow length
Allele from
Female
A
a
B b
C c
D d
E e
F
f
G g
H h
I
i
J j
K k
M1 M2
O o
P p
Q q
R1
R2
S1
S2
T t
U u
V
Z
v
z
A a
Allele from
Male
A a
B b
C c
D d
E e
F
f
G g
H h
I
i
J j
K k
M1 M2
O o
P p
Q q
R1
R2
S1
S2
T t
U u
V
Z
v
z
A a
Offspring’s
Genotype
Offspring’s
Phenotype
17
18
19
20
21
22
Mouth size
Lip thickness
Dimples
Nose size
Nose shape
Earlobe attachment
B1
C
D
E1
F
H
B2
c
d
E2
f
h
B1
C
D
E1
F
H
B2
c
d
E2
f
h
23
24
Hairy ears
Freckles on cheeks
K
L
k
l
K
L
k
l
25
Freckles on forehead
M
m
M
m
Follow-up Questions:
1. Define allele: _____________________________________________________________________
2. How many alleles does each parent have for each trait? ____________________
3. How many alleles will each parent pass to the offspring? ____________________
4. What type of cell division separates the alleles to form haploid cells? ________________
5. How many alleles does your baby carry for each trait? ______________
6. Would you predict that another pair of students in your class would have an offspring
genetically identical to yours? Explain. _______________________________________________
_____________________________________________________________________________________
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7. Is the principle of independent assortment represented in this activity? Explain.
_____________________________________________________________________________________
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8. Traits #7, 10, 11, 17, 20 are “incompletely dominant” traits. Based on your observations
of phenotypes, what does incompletely dominant mean? ____________________________
_____________________________________________________________________________________
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9. Traits #5, 6, 9 are “polygenic.” Based on the lab, what do you think polygenic means?
What kinds of phenotypes are seen in polygenic traits? _______________________________
_____________________________________________________________________________________
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10. a. Complete the Punnett square to show the possible parental genotypes of trait
#12, eye shape. What would the offspring look like (provide percentages)?
T
t
T = almond shaped
t = round shaped
T
t
b. Complete the Punnett square to represent the possible parental genotypes of
trait #7, hair type. What would the offspring look like (provide percentages)?
M1
M1
M2
M2
M1 = curly hair
M2 = straight hair