Bikini Bottom - Dihybrid Crosses Worksheet Template (Page 2 of 2) in pdf

6. 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.

A. What is Patti’s phenotype? _______________________________

B. Is it possible for the new couple to have offspring that resemble their mother? Explain.

___________________________________________________________________________

C. Before Patrick commits to this relationship, he would like to guarantee that his offspring

would have his thick eyebrows as he thinks they make him smarter! You need to provide

evidence for or against the marriage with regards to eyebrows ONLY.

7. While Squidward’s family boasts about being a purebred line for dominant light

blue skin color, they are also purebred for a less distinguished trait: the recessive

trait of baldness. Lack of hair causes Squidward some self-esteem issues that he

does not want his children to face. 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?

A. Must she have hair? Explain. _____________________________________________

Squidward Traits:

_______________________________________________________________________

Skin Color

Blue = B, Green = b

B. Must she be blue? Explain. _______________________________________________

Hair

________________________________________________________________________

Hair = H, Bald = h

C. 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's Genotype = __________ Octavia's Genotype = __________

D. Use the genotypes in above to complete the Punnett square below and then answer the questions.

____________

E. Answer these questions based on your Punnett square.

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? ________

Contributed by Andrea Stonebraker

Bikini Bottom - Dihybrid Crosses Worksheet Template Page 2