Virtual Fly Lab

Pre-lab preparation:

Watch the Bozeman Science Genetics of Drosophila demo video to get an idea of how the lab goes here:

https://www.youtube.com/watch?v=p9MpMr8qAAQ

Lab Day (PLAN A) (scroll down for plan B):

1. You can work individually or with a partner.

2. Go to http://sciencecourseware.org/vcise/drosophila/

3. Create a new account using the code: 14290694

(check out the tour feature for additional explanation/demonstration/help)

4. Execute the fly lab during the double period. You can save your data in the online notebook, though if you experience site problems sometimes this can be lost. The other option is to record as you go in a notebook/hard copy.

a. THREE crosses carried out to the F2 generation are required.

so for each cross, you will order 2 flies that will be your P generation, then mate 2 individuals from the F1 to get your F2.

b. Using the data you collect (the phenotypic results of the crosses) describe the pattern of inheritance for the traits you selected

(i.e. dominant/recessive, sex-linked/autosomal, lethal, etc.)

c. Include chi square analysis in your report to accept/reject the validity of your findings.

d. Cross 1 must be wild type X one mutation.

Cross 2 must be wild type X a different mutation.

Cross 3 must be wild type X a double mutant.

5. When finished, immediately begin writing up a formal lab report in your actual lab notebook of what you did.

a. Title and date

b. Problem: What inheritance patterns can be observed in the model organism Drosophila?

How can experiments be designed to determine inheritance patterns in crosses using Drosophila in a virtual fly lab.

c. Hypothesis: Base it on the traits you choose.

ex: If (some trait) is autosomal recessive (or sex-linked or dominant, or whatever),

then there should be (some ratio) of (some phenotype) in the F1 generation, and (some ratio) of (some phenotype) in the F2 generation.

d. Experimental Design: describe the crosses you will use to test your hypotheses.

e. Materials: list the items used in the virtual lab - like flies, bottles, ether, microscope, etc.

f. Procedure: Give a step by step of how you perform, complete, and observe crosses using fruit flies.

g. Data: resulting numbers from the crosses (like the different phenotypic classes observed from each cross).

Include both F1 phenotypic observations and F2 phenotypic observations.

h. Analysis: Statements of what the above numbers indicate about the pattern of inheritance for each mutation and the chi square results to back it up.

Ex: Gene Z appears to be recessive because in the F2 there is a 3:1 phenotypic ratio of wild-type to Z.

Chi-squared analysis shows that any variation from the expected outcomes is due to chance.

The calculated chi-squared value is less than the critical value of (whatever value because of whatever degrees of freedom), so the null hypothesis is accepted.

OR... Gene Z does not appear to be recessive, as originally proposed, because in the F2 there is not a straight forward 3:1 phenotypic ratio of wild-type to Z.

Chi-squared analysis shows that any variation from the expected outcomes is due to some other factor.

The calculated chi-squared value is more than the critical value of (whatever value because of whatever degrees of freedom), so the null hypothesis is rejected.

The observations instead indicate that perhaps... blah, blah, blah, and now propose some other idea that can be supported via some other mode of inheritance, ratios, and chi-squared.

i. Conclusion: The data and chi square analysis support that (some trait) is inherited (in whatever way) because... (explain the reasoning).

j. Post-lab: None.

6. Turn your in lab notebook by the assigned date for review by Dr. Kostenko.

Lab Day (PLAN B):

1. You can work individually or with a partner.

2. Obtain a monohybrid cross data set (includes 3 crosses for 3 different mutations) and a dihybrid cross data set (includes 2 crosses for 2 different double mutants).

3. Execute data analysis and draw conclusions during the double period.

a. for the three MONOHYBRID crosses determine if the traits are autosomal or sex-linked, dominant or recessive, lethal or non-lethal.

b. Include chi square analysis in your report to accept/reject the validity of your findings.

c. Defend/explain your findings citing genetic principles, observations (the data), and statistical analysis.

d. for the two DIHYBRID crosses determine if the traits are autosomal or sex-linked, dominant or recessive, lethal or non-lethal.

e. additionally determine whether the traits are linked on the same chromosome or if they are located on different chromosomes.

f. if you find linkage, determine how many map units apart the 2 genes are.

g. Include chi square analysis in your report to accept/reject the validity of your findings.

h. Defend/explain your findings citing genetic principles, observations (the data), and statistical analysis).

4. When finished, immediately begin writing up a formal lab report in your actual lab notebook of what you did.

a. Title and date

b. Problem: What inheritance patterns can be observed in the model organism Drosophila?

How can experiments be designed to determine inheritance patterns in crosses using Drosophila in a virtual fly lab.

c. Hypothesis: Base it on the traits you are given.

ex: If (some trait) is autosomal recessive (or sex-linked or dominant, or whatever),

then there should be (some ratio) of (some phenotype) in the F1 generation, and (some ratio) of (some phenotype) in the F2 generation.

d. Experimental Design: describe the crosses you will use to test your hypotheses.

e. Materials: list the items you would use to do this in real practice (research).

f. Procedure: Give a step by step of how you would perform, complete, and observe crosses using fruit flies.

g. Data: resulting numbers from the crosses (the data you were given).

h. Analysis: Statements of what the above numbers indicate about the pattern of inheritance for each mutation and the chi square results to back it up.

Ex: Gene Z appears to be recessive because in the F2 there is a 3:1 phenotypic ratio of wild-type to Z.

Chi-squared analysis shows that any variation from the expected outcomes is due to chance.

The calculated chi-squared value is less than the critical value of (whatever value because of whatever degrees of freedom), so the null hypothesis is accepted.

OR... Gene Z does not appear to be recessive, as originally proposed, because in the F2 there is not a straight forward 3:1 phenotypic ratio of wild-type to Z.

Chi-squared analysis shows that any variation from the expected outcomes is due to some other factor.

The calculated chi-squared value is more than the critical value of (whatever value because of whatever degrees of freedom), so the null hypothesis is rejected.

The observations instead indicate that perhaps... blah, blah, blah, and now propose some other idea that can be supported via some other mode of inheritance, ratios, and chi-squared.

i. Conclusion: The data and chi square analysis support that (some trait) is inherited (in whatever way) because... (explain/defend the reasoning).

j. Post-lab: None.

6. Turn your in lab notebook by the assigned date for review by Dr. Kostenko.