Case Study Accident On The Job Name Class

Case Study Accident On The Jobname Class

Case Study- Accident on the Job Name:___________________________ Class:_________ Cross Out the Mutation! You get to be a mutated fruit fly for the day. Your goal is to cross with other fruit flies in your class in order to create wildtype, or normal, flies. Read the procedure and answer the pre-lab questions before beginning.

Procedure:

• 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 therefore don’t 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 therefore don’t have the Curly mutation).

Here is an example of a cross:

Recessive Eyeless                    Dominant Curly

(ey/ey)                       (&+/+)

(Same logic applies for the other cross)

For both the Curly and eyeless crosses, flip a coin with your partner to see who gets to pick their genotype first.

For example, in the above crosses, both partners might be ey/+ but one will be Cy/+ and the other will be +/+.

If you have the eyeless phenotype, put the blindfold on; if you are Curly, start hopping; if you are wildtype, you can walk normally.

Remember, Curly is dominant and eyeless is recessive.

If your genotype is Cy/+, you have to hop; if your genotype is ey/+, you don’t have to wear the blindfold.

With your new genotype and phenotype, pick a classmate to do another cross with. Repeat this for four crosses. Your goal is to become a wildtype fruit fly.

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?

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?

Paper For Above instruction

The activity described involves simulating genetic inheritance patterns of specific mutations—namely eyeless and curly wing traits—in fruit flies through a classroom exercise. The primary goal is to understand Mendelian genetics, specific inheritance patterns of dominant and recessive traits, and the probabilities involved in crossing different genotypes to produce wildtype organisms. This activity not only reinforces theoretical concepts but also provides practical experience in predicting offspring genotypes and phenotypes, understanding the significance of dominant versus recessive alleles, and appreciating the results of multiple generations of genetic crosses.

In the activity, students are assigned the roles of fruit flies exhibiting specific mutations—eyeless or curly wings—which are governed by well-understood genetic alleles. The eyeless mutation is recessive, meaning that a fruit fly must inherit the “ey” allele from both parents to exhibit the eyeless phenotype. Conversely, the curly wing mutation is dominant; only one copy of the “Cy” allele is necessary for the fly to have curly wings. The activity involves performing multiple crosses with classmates, simulating the inheritance of these traits, and employing Punnett squares to determine the possible genotypes and phenotypes of the offspring.

The process begins by selecting a genotype—either "ey/ey" for eyeless or "Cy/+" for curly wings—based on a coin flip, introducing variability and mirroring natural genetic assortment. The students then use Punnett squares to predict the genotypes and associated phenotypes of the resulting offspring. The phenotypic expression depends on the alleles inherited: a fly with "ey/ey" genotype displays the eyeless phenotype, which requires wearing a blindfold; a fly with "Cy/+" genotype exhibits curly wings and must hop. Flies with wildtype traits—"+/+" for both genes—walk normally and do not wear restrictions.

The iterative process involves selecting new mates based on phenotypes and genotypes, then performing subsequent crosses to progressively accumulate wildtype traits within the simulated populations. This approach demonstrates how certain manipulations and probabilistic outcomes influence the distribution of traits in successive generations. The students’ predictions about the percentage of wildtype, eyeless, and curly flies at the end of the activity enable them to analyze the accuracy of Mendelian inheritance in a practical scenario.

The activity emphasizes the importance of understanding how dominant and recessive alleles interact, as well as how multiple genes influence phenotypic expression. Students learn that achieving a wildtype phenotype — with no mutations — involves combining alleles from multiple loci, which can be challenging but achievable through selective crosses. Furthermore, the activity illustrates the concept of genetic variability and how certain traits are inherited less frequently due to the probabilistic nature of genetic inheritance.

From a teaching perspective, the activity effectively demonstrates the principles of genetic inheritance, providing hands-on experience that reinforces theoretical knowledge. It also highlights the significance of chance and probability in Genetics, illustrating that genetic outcomes are not always predictable on an individual basis but follow statistical patterns across populations. This understanding is foundational in fields such as genetics research, breeding, and evolutionary biology.

References

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