Flies Lab Report Essay
Before one can begin the lab, he/she must make a prediction about what gene the trait one are analyzing is on. The trait can either be sex-linked, or autosomal.
To begin the lab, one must acquire a sample of flies to cross. These flies should be placed in a tube with an easily removable foam stopper. Use the flynap to knock out the fruit flies, and pour them out of the tube into a petri dish. Then place the petri dish on a stereomicroscope, and begin using a paintbrush to sort the flies by gender. Male flies have sex combs on their forelegs, and are usually smaller than the female flies. The females have pointed posteriors, do not have sex combs, and are usually larger.
Once the flies are sorted, one must make two to three culture vials for the flies to cross in. Place one cup of Drosophila medium and one cup of water in each vial. Label each vial the date and what one is crossing. Then put five to six …show more content…
Use the flynap to knock out the flies and count them using a stereomicroscope, sorting them with the paintbrush by gender and phenotype. Record this data as it will be used to determine one's prediction for what type of gene the trait was on.
Then using Punnett and Chi square analysis to determine whether one’s prediction was correct. Use this prediction to create a punnett square for the cross, and then find the expected ratios of the F1 phenotypes. Use both the predicted and observed values to undergo a Chi-square analysis. Doing the Chi-square analysis assumes that the prediction is correct, and tells one how likely it is that the results happened due to random variation rather than another factor.
If the results were likely to occur due to random variation, then the prediction was correct, but if they were unlikely to happen due to random variation then the prediction was incorrect and one should attempt to repeat the punnett and chi square analysis with the other
To begin the lab, one must acquire a sample of flies to cross. These flies should be placed in a tube with an easily removable foam stopper. Use the flynap to knock out the fruit flies, and pour them out of the tube into a petri dish. Then place the petri dish on a stereomicroscope, and begin using a paintbrush to sort the flies by gender. Male flies have sex combs on their forelegs, and are usually smaller than the female flies. The females have pointed posteriors, do not have sex combs, and are usually larger.
Once the flies are sorted, one must make two to three culture vials for the flies to cross in. Place one cup of Drosophila medium and one cup of water in each vial. Label each vial the date and what one is crossing. Then put five to six …show more content…
Use the flynap to knock out the flies and count them using a stereomicroscope, sorting them with the paintbrush by gender and phenotype. Record this data as it will be used to determine one's prediction for what type of gene the trait was on.
Then using Punnett and Chi square analysis to determine whether one’s prediction was correct. Use this prediction to create a punnett square for the cross, and then find the expected ratios of the F1 phenotypes. Use both the predicted and observed values to undergo a Chi-square analysis. Doing the Chi-square analysis assumes that the prediction is correct, and tells one how likely it is that the results happened due to random variation rather than another factor.
If the results were likely to occur due to random variation, then the prediction was correct, but if they were unlikely to happen due to random variation then the prediction was incorrect and one should attempt to repeat the punnett and chi square analysis with the other