Traits) Answers
Mouse Genetics (Two Traits)
Vocabulary: allele, genotype, phenotype, probability, Punnett square
[Note to teachers and students: This Gizmo was designed as a follow-up to the Mouse Genetics
(One Trait) Gizmo™. We recommend doing that activity before trying this one.]
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
[Note: The purpose of these questions is to activate prior knowledge and get students thinking.
Students are not expected to know the answers to the Prior Knowledge Questions.]
1. A single coin is flipped four times. What do you think is the most likely outcome?
A. Four heads D. One head, three tails
B. Three heads, one tail E. Four tails
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C. Two heads, two tails F. All are equally likely
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Answers will vary. [The correct answer is C: Two heads, two tails (3/8 probability).]
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2. What do you think are the odds of getting four tails in a row? Explain your answer.
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Answers will vary. [The correct answer is 1/16, or 6.25%. This is equal to (½)4, or 0.54.]
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Gizmo Warm-up
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On the Mouse Genetics (Two Traits) Gizmo, drag mice into the
Parent 1 and Parent 2 spaces, and then click Breed to see their
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offspring. Experiment with different combinations of parent mice.
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1. What must be true to have offspring with black fur?
At least one parent has black fur.
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2. What must be true to have offspring with white fur?
Answers will vary. [If both parents are homozygous, then both parents must have white fur.
White fur could also result if one or both of the parents are heterozygous for fur color.]
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3. What must be true to have offspring with black eyes? At least one parent has black eyes.
4. What must be true to have offspring with red eyes? Answers will vary (see above).
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5. What must be true to have offspring with red eyes and white fur?
Answers will vary. If both parents are homozygous for these traits, then both parents must
have red eyes and white fur. These traits could also result if one or both parents are
heterozygous for fur color and eye color.
This study source was downloaded by 100000828331062 from CourseHero.com on 08-08-2021 06:19:53 GMT -05:00
https://www.coursehero.com/file/26666430/Ashleigh-Snyder-Mouse-Genetics-Two-Traitsdocx/
, Activity A: Get the Gizmo ready:
Exploring ● Click Clear.
inheritance ● Turn on Show genotype.
Question: What patterns appear when two traits are inherited?
1. Observe: Breed a black-fur, black-eye mouse with a white-fur, red-eye mouse. Click Breed
several times, and then drag two of the offspring into the Holding Cages below. Move the
cursor over a mouse to see its genotype, or allele combination.
A. What is the genotype of the black-fur parent? FF EE
B. What is the genotype of the white-fur parent? ff ee
C. What are the genotypes of the offspring? All offspring are Ff Ee
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2. Analyze: The probability of an event is the likelihood that it will happen. Probability can be
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expressed as a percentage, such as 75%, as a decimal (0.75), or as a fraction (3/4).
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What is the probability that an offspring mouse will have black fur and black eyes? 100%
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3. Predict: Click Clear, and move the two mice from the Holding Cages into the parent box.
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What do you expect the offspring of these mice to look like? Predictions will vary.
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4. Experiment: Click Breed, and record the genotypes of the offspring on a sheet of paper.
Repeat this several times to see a variety of offspring. What genotypes do you see?
Possible offspring genotypes are FF EE, FF Ee, FF ee, Ff EE, Ff Ee, Ff ee, ff EE, ff Ee, and
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ff ee.
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5. Extend: Turn on Show statistics, and click Breed until there are 100 offspring.
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A. How many offspring have black fur and black eyes? Results will vary.
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B. How many offspring have black fur and red eyes? Results will vary.
C. How many offspring have white fur and black eyes? Results will vary.
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D. How many offspring have white fur and red eyes? Results will vary.
This study source was downloaded by 100000828331062 from CourseHero.com on 08-08-2021 06:19:53 GMT -05:00
https://www.coursehero.com/file/26666430/Ashleigh-Snyder-Mouse-Genetics-Two-Traitsdocx/