Name Class Cross Out The Mutation

Name Class Cross Out The Mutation

Read the procedure and answer the pre-lab questions before beginning. Your teacher will assign you to be an eyeless or curly winged fruit fly. If you are eyeless, you must wear a blindfold; if you are curly, you must hop to get around the classroom. Pick a classmate to cross with and fill out the first cross on the third page.

You need to make two Punnett squares for the two mutant genes. The “+” is the wildtype version of the gene, the “Cy” is the Curly gene, and the “ey” is the eyeless gene. For the eyeless cross, your genotype is “ey/ey” if you have the recessive eyeless mutation, and “+/+” if you have the Curly mutation (and do not have the eyeless mutation). For the Curly cross, your genotype is “Cy/+” if you have the dominant Curly mutation, and “+/+” if you have the eyeless mutation (and do not have the Curly mutation). An example of a cross: Recessive Eyeless × Dominant Curly. For both the Curly and eyeless crosses, flip a coin with your partner to decide who chooses their genotype first.

If you have the eyeless phenotype, put on the blindfold; if Curly, hop around; if wildtype, walk normally. Remember, Curly is dominant and eyeless is recessive, so if your genotype is Cy/+, you must hop; if ey/+, then you do not wear the blindfold. Using your new genotype and phenotype, pick a classmate for another cross. Repeat this for four crosses, aiming to become wildtype.

Prelab Questions

• What strategies do you plan to use to make wildtype flies?
• What percentage of the class do you anticipate will be wildtype at the end? Eyeless? Curly?

Cross 1:

Your phenotype: ___________________

Your genotype: ____/____, ____/____

Your mate’s phenotype:___________________

Your mate’s genotype: ____/____, ____/____

Your new genotype: ____/____, ____/____

Your new phenotype:___________________

Cross 2:

Your mate’s phenotype:___________________

Your mate’s genotype: ____/____, ____/____

Your new genotype: ____/____, ____/____

Your new phenotype:___________________

Cross 3:

Your mate’s phenotype:___________________

Your mate’s genotype: ____/____, ____/____

Your new genotype: ____/____, ____/____

Your new phenotype:___________________

Cross 4:

Your mate’s phenotype:___________________

Your mate’s genotype: ____/____, ____/____

Your new genotype: ____/____, ____/____

Your new phenotype:___________________

Results and Analysis

What percentage of the class had each genotype and phenotype at the end?

How does this compare with your prediction?

What was the best strategy for making wildtype flies?

What did you learn from this activity?

References

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