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Bikini Bottom – Dihybrid Crosses

Name ________________________________

Use the chart to identify the genotypes of the following traits:
1. Heterozygous round eyes, blue body ________
2.Hybrid eye shape, purebred roundpants ________
3. Purebred roundpants, heterozygous long nose ________

Trait
Body Shape
Body Color
Eye Shape
Nose Style

Dominant Gene
Squarepants (S)
Yellow (Y)Round (R)
Long (L)

Recessive Gene
Roundpants (s)
Blue (y)
Oval (r)
Stubby (l)

4. SpongeBob’s aunt, who is a roundpants, has a cute stubby nose. She has finally found the sponge of herdreams
and is ready to settle down. Her fiancé always comments on how adorable her nose is (he says it reminds him of his
mother’s – aww, how sweet!). They wonder what the chances are of that traitbeing passed on. Her fiancé is a
purebred squarepants and is a hybrid for his long nose.
A. Identify the genotypes of the aunt and her fiancé.
Aunt = Roundpants, Stubby Nose = ________

Fiancé =Purebred Squarepants, Long Nose = ________

B. What are the possible gamete combinations for each person?
Aunt = ______________________________

Fiancé = ______________________________

C. Whatare the possible genotypes for their children? ______________________________________

5. As we know, SpongeBob is heterozygous for his yellow body color and his squarepants, while his wifeSpongeSusie is blue and has roundpants. Use this information to answer the following questions.
A. Give the genotypes for each.
SpongeBob = __________________

SpongeSusie = _______________

B. What arethe possible gamete combinations for each person?
SpongeBob = __________________

SpongeSusie = __________________

C. Complete the Punnett square based on the information provided in #5.____________

____________

____________

____________

____________
____________
____________
____________
D. Answer the questions based on your Punnett square.
What is the chance of a blue...