Name:
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Spock’s Ears
INTRODUCTION: Mr. Spock is a science fiction character on the television, Star Trek. According to Star
Trek’s story line, Mr. Spock is a hybrid or an organism produced from two parents with differing characteristics.
Spock’s mother is a female earthling and his father belongs to the fictional race of Vulcans. On this worksheet,
you will answer questions relating to the genetic history of Mr. Spock’s pointed ears.
The gene pair that controls the upper ear structure of Spock’s father’s pointed ears is the homozygous
dominant genotype PP.
The gene pair that controls the upper ear structure of Spock’s mother’s rounded ears is the homozygous
recessive genotype pp.
In the space below, show the possible gene pairing that could result in the offspring of Spock’s mother and
Spock’s father.
1. Why is Mr. Spock heterozygous?
2. What is the phenotype of Spock’s upper ear structure?
3. What is the genotype of Spock’s upper ear structure?
4. What was the genotype of Spock’s father’s upper ear structure? What word is used to describe an
organism with two identical alleles for a particular trait?
5. What was the genotype of Spock’s mother’s upper ear structure?
SHOW WORK TO SUPPORT YOUR ANSWERS TO QUESTIONS #6-8.
6. If Spock marries an earthling, what percentage of the offspring will be heterozygous for ear structure?
Although you may be an exception, assume all earthlings have rounded ears.
7. If Spock marries a woman from the race of the Vulcans who is homozygous dominant, what percentage
of their offspring will also be homozygous dominant like their mother?
8. If Spock marries someone who is heterozygous for ear structure like himself, what percentage of the
offspring will have rounded ears?