A Study Of Inheritable Traits In Fruit Flies Essay -- fruit fly geneti

A Study Of Inheritable Traits in Fruit Flies INTRODUCTION The Drosophila melanogaster, more commonly known as the fruit fly, is a popular species used in genetic experiments. In fact, Thomas Hunt Morgan began using Drosophila in the early 1900’s to study genes and their relation to certain chromosomes(Biology 263). Scientists have located over 500 genes on the four chromosomes in the fly. There are many advantages in using Drosophila for these types of studies. Drosophila melanogaster can lay hundreds of eggs after just one mating, and have a generation time of two weeks at 21Â °C(Genetics: Drosophila Crosses 9). Another reason for using fruit flies is that they mature rather quickly and don’t require very much space. Drosophila melanogaster has a life cycle of four specific stages. The first stage is the egg, which is about . 5mm long. In the 24 hours when the fly is in the egg stage, numerous cleavage nuclei form. Next, the egg hatches to reveal the larva. During this stage, growth and molting occur. Once growth is complete, the Drosophila enter the pupal stage, where it develops into an adult through metamorphosis. Upon reaching adulthood, the flies are ready to mate and produce the next generation of Drosophila melanogaster. During this experiment, monohybrid and dihybrid crosses were conducted with Drosophila melanogaster. Our objective was to examine the inheritance from one generation to the next. We collected the data from the crosses and analyzed them in relation to the expected results. MATERIALS AND METHODS For the monohybrid cross in this experiment, we used an F1 generation, which resulted from the mating of a male homozygous wild-type eyed fly with a female homozygous sepia eyed fly. Males and females are distinguished by differences in body shape and size. Males have a darker and rounder abdomen in comparison to females, which are more pointed. Another difference occurs on the forelegs of the flies—males have a small bump called sex combs. At week 0, after being anaesthitized by fly-nap, three males and three females were identified under a dissecting microscope and placed in a plastic vial with a foam stopper at the end. The vial remained on it’s side until the flies regained consciousness so that they didn’t get trapped by the culture medium at the bottom. We allowed the Drosophila to incub... ...eighed the number of males. This may imply that the X chromosome is dominant over the Y chromosome. This would cause the X chromosome to mix with another X chromosome, producing a female, more often than it would mix with the Y chromosome, which would produce a male. As a follow-up to the experiment, I would perform many more trials than each person did for this experiment. Also, more flies could be placed in each vial to ensure even more offspring to be included in the data. I would also be sure to remove the flies after just one week to reduce breeding between generations. This experiment caused Mendel’s findings to be more concrete and realistic in my mind. It made the information more than meaningless numbers. The experiment also made me realize how easily biological ideas can be proved. Our results agree with Mendel’s discoveries. The only drawback to our learning was the massacre of over 26,000 fruit flies. REFERENCES Campbell, Neil A., Biology: Fourth Edition. Menlo Park: Benjamin/Cummings, 1996. "Genetics: Drosophila Crosses." Lab Handouts, General Biology Lab, 2008. "So What’s a Monohybrid Cross Anyway?" Lab Handouts, General Biology Lab, 2008.