Mouse Genetics (One Trait)
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Pre-lab questions:
1. Define genotype.
2. What is an allele?
3. What is a dominate allele?
4. What is a recessive allele?
5. Define hybrid.
Post-lab questions:
1. Define gene.
2. Define heredity
3. What does heterozygous mean?
4. What doe homozygous mean?
5. What is inheritance?
6. What is phenotype?
7. What is a Punnett Square?
8. What is a trait?
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In this activity, you will experiment with different combinations of mouse parents to see how fur color is passed to their offspring.
Answer all # questions on a separate piece of paper!
· Go to www.explorelearning.com and login.
o USERNAME: CBB339, PW: wind118
· On the Biology page, click on the Mouse Genetics (One Trait) gizmo.
A. Breed different combinations of mice. As you do, consider the following questions:
Drag and drop mice on the ‘Parent 1’ and ‘Parent 2’ slot. Answer question (a). Click BREED.
Answer question (b). Repeat using a different combination of parent mice. Answer (c) after
trying the same combination of parents multiple times.
a. What color offspring do you expect to result from each set of parents?
b. What color offspring do you actually get from each set of parents?
c. Does your data change the more times you mate each set of parents?
1. What does it mean to be ‘pure’?
2. What color is dominant?
3. What color is recessive?
B. Mate a black and white mouse. Drag two of the offspring mice into the Holding Cages at the bottom of the Gizmo. Continue to breed different combinations of mice, you may mate the original mice with the ones in the holding cages. As you do, consider the following questions:
a. What color offspring do you expect to result from each set of parents?
b. What color offspring do you actually get from each set of parents?
c. Does your data change the more times you mate each set of parents?
4. What is the result when you mate the two hybrid black offspring?
Click show genotype (in the right hand corner). Repeat ALL of your experiments (A and B, including only the bold questions). As you do, also consider the following questions:
a. Are the letters always the same?
b. Why are some letters capitalized?
5. How many letters does each mouse have?
6. Where does each of the letters come from?
7. Why are some letters capitalized and some not?
8. Did seeing the genotypes (letters) help explain any of your of earlier conclusions?
Create two hybrid mice and drag them to the holding cages for your next experiments. (Mate a pure white with a pure black to make a hybrid).
Drag the two mice from the holding cages into the Parent 1 and Parent 2 spot. Highlight them (hold pointer over mouse – you do not need to click). Place the two mice as ‘Parent 1’ and ‘Parent 2.’ DO NOT click breed yet.
Make sure their genotypes are Ff and Ff. If they are not FIX IT!
To predict how parents pass on traits to their offspring, geneticists use a diagram called a Punnett Square. See the Punnett Square below. In the Punnett Square, the parents’ genotypes are written along the side and top, separating the letters so that they correspond with the boxes. Notice this done below. Then, genetists bring the letters across and down filling in the squares, as shown below.
9. Copy the Punnett Square from above onto your paper and finish filling in the squares.
10. Based on this information, and the conclusions you have drawn so far, how many mice, out of four, would you expect to be Black?
Click breed and look at the offspring. As you do, consider the following question:
a. Does your predicted outcome (from your punnett square) match your actual outcome (from the gizmo)?
Select “Show Statistics” and continuing breeding your mice until you have generated 100 offspring.
11. How do the numbers of black and white offspring compare to what you predicted?
BONUS: Write Question & All Possible answers down.
12. Answer assessment questions 1-5. Try to use a Punnett Square to answer questions.
Click CHECK ANSWER. Click CONTINUE.
13. Review your answers. Correct the questions you did not get correct and write down the explanation provided for EACH question.