4. SpongeBob SquarePants recently met SpongeSusie Roundpants at a dance. SpongeBob is heterozygous for his square shape, but SpongeSusie is round. Create a Punnett square to show the possibilities that would result if SpongeBob and SpongeSusie had children. HINT: Read question #2!

Question

A. List the possible genotypes and phenotypes for their children. ___________________________
B. What are the chances of a child with a square shape? ____ out of ____ or ____%
C. What are the chances of a child with a round shape? ____ out of ____ or ____%

Answer 1

To solve this problem, we first need to establish the genotypes for SpongeBob and SpongeSusie.

Let's denote:

• \( S \) = allele for square shape (dominant)
• \( s \) = allele for round shape (recessive)

Since SpongeBob is heterozygous for his square shape, his genotype is \( Ss \). SpongeSusie, being round, is homozygous recessive, so her genotype is \( ss \).

A. Create a Punnett Square

          S       s
       -----------------
     |   S   |  Ss  |  Ss  |
     |-------|-------|-------|
     |   s   |  ss   |  ss   |

Possible Genotypes and Phenotypes

From the Punnett square, the possible genotypes for their children are:

1. \( Ss \) (Square shape)
2. \( ss \) (Round shape)

Possible phenotypes:

• Square shape (from genotype \( Ss \))
• Round shape (from genotype \( ss \))

B. Chances of a Child with a Square Shape

• Genotype \( Ss \): 2 out of 4
• Probability: \( \frac{2}{4} \) or \( 50% \)

C. Chances of a Child with a Round Shape

• Genotype \( ss \): 2 out of 4
• Probability: \( \frac{2}{4} \) or \( 50% \)

Summary:

• Possible genotypes: \( Ss \), \( ss \)
• Possible phenotypes: Square shape, Round shape
• Chances of a child with a square shape: 2 out of 4 or 50%
• Chances of a child with a round shape: 2 out of 4 or 50%