Name: _____________________________ Class: _______ Date: _________________
Try a Trihybrid Cross!
You are a world-famous breeder of Purple-People Eaters ("PPE"). Tragically, your entire
stock perishes in a fire except for two individuals. They are both heterozygous for all
three traits desired. The three traits are as follows:
EE/Ee-two eyes
HH/Hh-two horns
FF/Ff-non flying
ee-one eye
hh-one horn
ff-flying
The traits that bring the big bucks ($100 each) are "one eyed, one horned, flying" purple
people eaters. If you breed the remaining two PPE, what distributions of traits will you
get?
1. What are the genotypes for the parents? ______________ X ______________
2. What genotypes will the gametes carry? Hint: Remember that a gamete carries half
the genetic information for each trait.
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3. Use a Punnett square to show the results of this particular pair of Purple-People
Eaters.
Name: _____________________________ Class: _______ Date: _________________
4. What are the possible phenotypes that would be seen in the offspring?
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5. In the Punnett Square, color the squares that represent the desired 3-trait combination
of being one-eyed, one-horned & flying in the Purple-People Eater offspring.
6. What is the probability that the Purple-People Eater offspring will have all three of
the traits (one-eyed, one-horned & flying) so that you will be able to sell them for
those big bucks ($100 each)?
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7. It costs $25 to raise each Purple-People Eater. Will it be cost effective (get a lot of
them critters) or shall you buy yourself fresh breeding stock of a different genotype?
Briefly explain.
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8. What is the probability that the Purple-People Eater offspring would have the traits of
being 2-eyed, 2-horned & flying?
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