1. Heterozygous round eyes, blue body: RrYy
2. Hybrid eye shape, purebred roundpants: RRSs
3. Purebred roundpants, heterozygous long nose: RrLL
4. Aunt - Roundpants, Stubby Nose: Rrll
Fiancé - Purebred Squarepants, Long Nose: SsLL
5. Aunt - RL, rl
Fiancé - SL, LL
6. Possible genotypes for their children: Squarepants with either round or oval eyes, and either long or stubby nose.
7. SpongeBob - SsYy
SpongeSusie - ssyy
8. SpongeBob - SY, Sy, sY, sy
SpongeSusie - sy
9. Punnett square:
SY Sy sY sy
----------------------------------------
sy | SYsy | Sssy | SYY | Syy
----------------------------------------
sy | SYsy | Sssy | SYY | Syy
What is the chance of a blue baby? 75%
What is the chance of a squarepants? 50%
What is the chance of a blue squarepants? 25%
What is the chance of a purebred recessive for both traits? 0%
10. Patti's phenotype is orange body color and thin eyebrows.
It is not possible for the new couple to have offspring that resemble their mother because Patrick does not carry the recessive traits for body color or eyebrow thickness.
11. Patrick can guarantee that his offspring will have thick eyebrows because he is purebred for that trait.
12. Squidward should look for a bride who is heterozygous for both traits (BbHh).
Must she have hair? Yes, because Squidward is purebred for hair.
Must she be blue? Yes, because Squidward is purebred for blue skin color.
13. Squidward = BbHh
Octavia = bbHh
14. Punnett square:
Bb bb
---------------------
Hh | BbHh | bbHh
---------------------
For which traits, if any, is it possible for their offspring to be purebred? Hair trait.
What is the probability of their children being heterozygous for both traits? 50%
Bikini Bottom – Dihybrid Practice
Use the chart to identify the genotypes of the
following traits:
Trait
Dominant Gene
Recessive Gene
Body Shape
Squarepants (S)
Roundpants (s)
Body Color
Yellow (Y)
Blue (y)
Eye Shape
Round (R)
Oval (r)
Nose Style
Long (L)
Stubby (l)
1. Heterozygous round eyes, blue body ________
2. Hybrid eye shape, purebred roundpants ________
3. Purebred roundpants, heterozygous long nose ________
SpongeBob’s aunt, who is a roundpants, has a cute stubby nose. She has finally found the sponge of her dreams 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 trait being passed on. Her fiancé is a purebred squarepants and has a purebred long nose.
4. Identify the genotypes of the aunt and her fiancé.
Aunt – Roundpants, Stubby Nose = ________
Fiancé – Purebred Squarepants, Long Nose = ________
5. What are the possible gamete combinations for each person?
Aunt – ________
Fiancé – ________
6. What are the possible genotypes for their children? ______________________________________
7. What are the genotypes of SpongeBob, who is heterozygous for his yellow body color and his squarepants, and his wife SpongeSusie, who is blue and has roundpants?
SpongeBob = ________
SpongeSusie = ________
8. What are the possible gamete combinations for each person?
SpongeBob = ________________
SpongeSusie = ________
9. Complete the Punnett square based on the information provided in #7-8 and then answer the questions.
What is the chance of a blue baby? ________
What is the chance of a squarepants? ________
What is the chance of a blue squarepants? ________
What is the chance of a purebred recessive for both traits? ________
10. In starfish, pink body color (P) is dominant to orange (p), and thick eyebrows (T) are dominant over thin (t) ones. Patrick, who is heterozygous for body color but purebred for thick eyebrows, has met Patti, who is recessive for both traits.
What is Patti’s phenotype? _______________________________
Is it possible for the new couple to have offspring that resemble their mother? Explain.
________________________________________________________________________
________________________________________________________________________
11. Before Patrick commits to this relationship, he would like to guarantee that his offspring would have his thick eyebrows. (He thinks they make him smarter!) You need to provide evidence for or against the marriage. This question regards eyebrows ONLY.
_________________________________________________________________
________________________________________________________________
12. While Squidward’s family boasts about being a purebred line for dominant
blue skin color, they are also purebred for a less distinguished trait: the recessive trait of baldness. He would like to ensure that his offspring have hair AND with his blue skin color. What traits should he look for in a bride?
Squidward Traits:
Skin Color
Blue = B, Green = b
Hair
Hair = H, Bald = h
Must she have hair? Explain. ____________________________________________________
Must she be blue? Explain. ____________________________________________________
13. Squidward has found a potential bride prospect with the green squid Octavia. While Octavia has hair, her father does not. Determine the chances of their child being blue and having hair.
Squidward = ________
Octavia = ___________
14. Use the genotypes in #13 to complete the Punnett square below and then answer the questions.
For which traits, if any, is it possible for their offspring to be purebred?____________
What is the probability of their children being heterozygous for both traits? ________
1 answer