Introduction
In most kitchens the small flies that are found are Drosophila Melanogaster also called fruit fly. They are often brought in by ripened tomatoes, grapes and other perishable items from the garden. Drosophila melanogaster is a little two winged insect about 3mm long two winged insect that belongs to the Diptera, the order of the flies. The drosophila egg is about half a millimeter long. Fertilization takes about one day the embryo to develop and hatch into a worm-like larva. The larva eats and grows continuously, after two days as a third in star larva; it moults one more time to form an immobile pupa. Over the next four days, the body is completely remodeled to give the adult winged form, which then hatches from the pupal
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Some larva containing vials had hatched into flies. Counting of the flies began at this point. As flies started to grow, at different rates for each vial, with in the first seven days after all larva had hatched the flies were counted. The procedure was done according to theDrosophila manual (45-2620)
Results
F1 Predictions
For our first generation (F1) of flies we chose to cross apterous (+) females and white-eye (w) males. We predicted that the mutation would be sex linked recessive. So if the female was the sex with the mutation then all females would be wild type heterozygous. Heterozygous is a term used when the two genes for a trait are opposite. The males would all be white eye since they only have one X chromosome. If the males were the sex that had the mutation then all the flies would be wild type but the females would be heterozygous.
F1 Outcomes
From the cross white eye males with wild females, our results were we got both phenotypes in the males as well as the females to be wild type.
F2 Predictions
Based upon observation of the F1 generation, we hypothesize that the inheritance of the white-eye (W) mutation is sex-linked and recessive wild type.
For the F2 generation the phenotype that was obtained is as followed. See Figure1.
|Normal wings |Normal wings |No wings white |No wings |
|Red eyes |White
Figure 4. This graph depicts the average allele frequency of male cichlid fish when a mutation that goes from recessive to dominant arises within the population at a rate of 0.001. The average value over five trials is shown to be 0.318.
4. Clear wing, Black eye, and Hairless (c, b, and h) are linked, recessive traits carried on
One possible error that may have occurred was that some of the adult flies may have accidentally been left in the vials with their offspring,
The parents are both homozygous. The homozygous dominant would represent the wild type. And the homozygous recessive would represent the other fly parent of a different strain. The F1 generation would consist of 100% Wild Type but they would all be heterozygous in carrying the recessive gene.
It was decided that there would be 80 vestigial flies and 20 wild type flies to total to an initial population of 100 drosophila. Next, the flies were anesthetized flies using Fly Nap. The flies were counted out to reach desired ratio, sexing the flies making sure there are equal amounts of males and females to be sure there is ample individuals to allow successful mating. The fly’s food was prepared by taking a frozen rotten banana, cutting it in half, mashing up the banana meat, and mixing yeast into it. The
Introduction: The intention of this lab was to gain a better understanding of Mendelian genetics and inheritance patterns of the drosophila fruit fly. This was tasked through inspecting phenotypes present in the dihybrid crosses performed on the flies. An experimental virtual fly lab assignment was also used to analyze the inheritance patterns. Specifically, the purpose of our drosophila crosses is to establish which phenotypes are dominant/recessive, if the traits are inherited through autosome or sex chromosomes and whether independent assortment or linkage is responsible for the expressed traits.
It would be expected that the mutant F1 flies would be heterozygous for the allele responsible for the grounded trait. If two F1 flies were mated, the percentage of flies that would be expected to be wildtype in the F2 generation would be 25% mutants given that the mutant allele (ap) is predicted to be recessive and, leaving 75% to be wildtype (ap+).
This lab had 2 exercises. Exercise 9.1 involved observing pictures of 60 F2 offspring and recording the phenotypes for 6 different traits. Exercise 9.2 required us to perform the “chi-square test” to determine whether the data we collected matches the standard Mendelian ratio.
There were eight different phenotypes among the progeny. The highest phenotypic frequency was the w+m+f+ at 40% of the progeny. The lowest was the w+mf+ with only 2 % of the progeny (Table 3). The sum of the recombinant frequencies between genes, table 4, was used to determine the gene distance. The recombinant frequency was determined by counting the number of individuals whose genes differed from that of the parental type. For example, how many individuals white eye gene, and miniature wing gene, differed from both wild-type or both mutants. Recombination occurred between the white and miniature gene 33 times. Recombination occurred between the miniature and the forked genes 31 times. Recombination occurred between the white and forked genes 44 time. Double recombination occurred 10 times. Therefore, genes w and f are 64 m.u. apart, m and w are 33 m.u. apart, and m and f are 31 m.u. apart (Figure
11. The progeny of a Drosophila female (heterozygous at three loci: y, ct, and w) crossed to a wild type male are listed below:
METHODS: In this experiment, the instructor provided us with 30 ebony individuals and 20 wild type individuals. In order to get an exact amount of each type, we anesthetized the flies and counted them off by gently using a fine point paint brush. Then all 50 Drosophila were put into a population cage which had a lid that had six holes for the centrifuge tubes. Two food tubes and four clean, empty tubes were added on the first day. Each food tube consisted of half a cup full of food mixed with 6-7 milliliters of water. This was the fly medium. The food should turn blue once the water is added. Each tube was labeled with a number and with the date. Every two to three days we added one more food tube until all 6 tubes contained the fly medium. After all 6 tubes were filled, the following days after we exchanged the first food tube with a new food tube. At the end of the experiment, we fed the flies with a total of 8 food tubes. Then the flies were anesthetized, again. At the end of this four week lab, the number of living ebony and wild
we said goodbye and placed them in the fly morgue. We allowed the F2 larval
We then kept the vial with the juvenile Drosophila for another 2 weeks in the same conditions as above and found that the F1 generation had hatched and laid eggs of their own. We then decanted the F1 generation into alcohol to kill them and kept them aside to score. The vial containing the new generation F2 of Drosophila was then kept for use in a further experiment.
Drosophila melanogaster is a small fruit fly that feeds on fruit and the fungi growing on spoiled fruit. Fruit flies have been used in the research end of the scientific community for over a century due to their interesting physical and behavioral characteristics, their practicality and small size, and their short life cycle of about fourteen days. Its behavior has been the focus of many experiments, beginning with Thomas Hunt Morgan in 1907, and continues today in the laboratories of high school classrooms. In this experiment we are investigating the relationship between a model organism, Drosophila, and its response to different environmental conditions. Our results from the chi-square analysis data all showed signs of our observed fly count
The pairs of alternative traits examined segregated among the progeny of a particular cross, some individuals exhibiting one traits, some the other