Drosophilia Lab Report
This was done so e could determine the mode of Inheritance of the genetic trait of body color and eye color. The mode of Inheritance was different for all of the crosses but all deal with Mender’s principles. Our results from the chill square analysis data all showed signs of our observed dating matching almost exactly to our expected data. Introduction Drosophila melanomas are very useful tools in the study of genetics. Drosophila are the most commonly used organism in genetic labs, because they have a short life span and they are a very simple organisms genetically.
In this experiment we are opining to determine phenotypes ratios and dominant vs.. Recessive traits by cross breeding two different types of Drosophila; such as wild type flies (tan bodies) with golden body fly mutants, and wild type flies (red eye) with dark eye drosophila. When crossing the wild-type tan body fly with the mutant golden body fly we will expect to see a 3:1 ratio in the Fl Generation. For every three wild type tan bodies flies we will expect to see one golden bodied fly. We would expect to see the same outcome for the IF Generation.
The trait for body color is autocross recessive in the golden bodied drosophila. The allele for the tan body’s dominant over the recessive golden body, because tan bodies are standard in flies where as golden bodies are a recessive mutant allele. After collecting data from the entire class and performing a chi square analysis we were able to determine that our predictions are correct. Methods and Materials First we had to set up the food in the vials for the future larva and files for the Pix crosses with true breeding parental flies.
We started by obtaining a transparent glass vial and placing three scoops of Formula 4- 24 Instant Blue Drosophila Food (Carolina Biological Supply Co. , Burlington, NC). Then we added approximately 0. 5% proportion acid to the dry food to get it moist. Then we added some yeast pellets for when the flies are grown and placed a foam plug In the opening of the vial. Then we transported flies from another vial given to us to the empty glass vial where they were chilled In a container of Ice. We then waited one minute for the flies to stop moving/flying.
While we were walling for the flies to become unconscious we scooped Ice onto a plastic tray then laid a metal outlet plate onto the Ice tray and let hat become cold. Then we poured the unconscious flies onto the outlet plate and use a dry paintbrush to move them around. The unconscious flies were then placed onto a plain white index card. A dissecting microscope was used to help identify the the flies’ abdomen and their sex combs. We left the vial lying horizontally so the flies didn’t get absorbed by the moisture of the food while they were still knocked out.
Once the flies woke up the vials were left standing vertically under a light to make sure that they stayed at room temperature. We labeled the vial with a piece of tape. We prepared a new culture vial with Formula 4- 24 Instant Blue Drosophila Food by repeating the same steps. We than selected 4 males with golden bodies. We did this by chilling them and following the steps previously done. 5 female virgin flies from my wild type tan subculture were added into the vial.
It is important for the females of the parental generation to be virgins because this assures us that all genetic/ breeding crosses that are done are from the parents of the most recent generation. If not, an offspring can be seen as a parent during experimentation. We added the 4 olden bodied male’s as well. We laid the vial horizontally until the 4 males woke up and became active again. We prepared a new culture vial by repeating the steps previously used. At this time the female wild- types and the male mutants have mated.
Pupa had collected on the sides of the glass vial. It was time to sex the female and male adult flies from the Fl culture. We chilled the flies in vials and then put them on a metal outlet plate, so that we could view them under a dissecting scope. Once we sexed them we added 4 females and 4 males from the Fl generation into the vial that was prepared. After the flies had woken up we placed the vial vertical, and waited for the flies to mate. We then did a chi square analysis to see if we could accept our null hypothesis.
We also did punned squares to figure out the phenotypes ratios of the Fl and IF generations. Results Discussion All of our data from the experiment turned out to be correct. No error occurred and we received data that was testable and helped us determine our hypothesis. Our observed data matched what we predicted in our hypothesizes. Each hypothesis that we predicted is supported by our results. The P value’s from the chi square analysis charts shows you a percentage and we had nothing higher than a 7% rate of error.
Ultimately our chi square analysis held the power to let us know whether or not our experiment was going to be a success or not. It turned out that it was. This lab was a learning experience for the whole class. It helped us understand how traits are transmitted through the use of a simple organism Drosophila melanomas. It also taught us how to be organized and keep information in spatial order. Having an experiment like this one makes us all more comfortable with the much more difficult ones we will face in the future of our college careers.