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Name____________________________________________________
Heredity Lab: Making Ugly Babies from a Shallow Gene Pool
Background Information
As you look around the room, you can see that no one else is exactly like you. One of the reasons for the
success of sexually reproducing species is the abundance of variations that appear within each generation
of offspring. Because genes are randomly inherited from each parent, each individually created offspring
will be absolutely unique.
In this laboratory, you will be performing “coin tosses” to simulate the passing of alleles from parents to
offspring for a variety of traits. Heredity is, of course, much more complicated than tossing coins but this
simulation provides a simplified model of how genes are passed on from one generation to the next, and
how those genes are related to the traits seen in the offspring. We have taken some liberties in simplifying
some of these traits – please note that many of these traits are controlled by multiple genes and exhibit
much more elaborate modes of inheritance than what is shown here.
Materials: Coins (2 per team) and Colored pencils
Procedure
1. Determine the sex of your “baby”. Working with a partner, shake both coins in hand, and release coins
onto the table top.
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If both coins come up heads or both come up tails, your baby is a GIRL.
If one coin comes up heads and the other comes up tails, your baby is a BOY.
2. Determine the traits of your “baby”. For each trait in the charts found on the next two pages, you will
perform one coin toss.
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If both coins come up HEADS, the baby will show the DOMINANT trait.
If both coins come up TAILS, the baby will show the RECESSIVE trait.
If one coin comes up heads, and the other comes up tails, the baby will show the HYBRID trait.
Sometimes the hybrid trait is the same as the dominant trait, and other times it is a blend
between the dominant and recessive traits.
3. As you complete each coin toss, be sure to complete the Data Table on the next page, indicating your
baby’s inherited GENOTYPE and PHENOTYPE for each trait. Use the Characteristics Chart as your guide to
the genotypes and phenotypes.
4. Once you have collected all the traits of your baby, draw a picture of your baby on the last page.
5. Answer the analysis questions.
DATA TABLE:
TRAIT
Sex
Length of eyelashes
Shape of eyebrows
Size of nose
Shape of lips
Size of ears
Size of mouth
Freckles
Dimples
Color of hair
Ability to roll tongue
Shape of face
Cleft in chin
Hair Texture
Widow’s peak
Shape of eyes
Position of eyes
Size of eyes
Spacing of eyes
Size of feet
Color of eyes
GENOTYPE PHENOTYPE
Characteristics Chart
Trait
Dominant
(both heads)
Hybrid
(one head, one tail)
Recessive
(both tails)
Round (RR)
Round (Rr)
Square (rr)
No cleft (CC)
No cleft (Cc)
Cleft in Chin(cc)
Curly (HH)
Wavy (Hh)
Straight (hh)
Widow’s Peak (WW)
Widow’s Peak (Ww)
No Widow’s Peak (ww)
Almond (AA)
Almond (Aa)
Round (aa)
Straight (SS)
Straight (Ss)
Slant upwards (ss)
Large (LL)
Medium (Ll)
Small (ll)
Close together (EE)
Average Distance (Ee)
Far apart (ee)
Large (FF)
Medium (Ff)
Small (ff)
Brown (BB)
Green (Bb)
Blue (bb)
Length of Eyelashes
Long (LL)
Long (Ll)
Short (ll)
Shape of eyebrows
Bushy (HH)
Bushy (Hh)
Fine (hh)
Size of nose
Large (LL)
Large (Ll)
Small (ll)
Shape of lips
Thick (KK)
Thick (Kk)
Thin (kk)
Size of ears
Large (EE)
Large (EE)
Small (ee)
Size of mouth
Large (MM)
Large (Mm)
Small (mm)
Freckles
Freckled (FF)
Freckled (Ff)
Not freckled (ff)
Dimples
Dimpled (DD)
Dimpled (Dd)
Not dimpled (dd)
Color of hair
Brown (WW)
Brown (Ww)
Blond (ww)
Can roll tongue (RR)
Can roll tongue (Rr)
Can’t roll tongue (rr)
Shape of Face
Cleft in Chin
Hair texture
Widow’s peak
Shape of eyes
Position of eyes
Size of eyes
Spacing of eyes
Size of feet
Color of eyes
Ability to roll tongue
Analysis Questions
1. What do the coins represent in this laboratory? (1pts)
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2. What does the flipping of each coin represent in this laboratory? (1pts)
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3. The parents in this laboratory have the same type of genotype for each trait. Are the parents
heterozygous or homozygous for each trait? How do you know? (2pts)
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4. Why do you only use one coin for each parent? (2pts)
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5. What biological process does bringing the results of each coin flip together represent? Explain. (3pts)
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6. What is the probability that an offspring from these parents will have a baby with freckles? Show the
cross (Punnett Square) to prove it. (2pts)
Probability:_____________________
7. Explain why finding the traits of an offspring produced asexually does not require a Punnett Square.
(3pts)
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Picture of Baby
Grading
Data Table – 21pts
Picture of Baby – 5pts
Analysis Questions – 14pts
Total Points – 40pts