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A Study Of Inheritable Traits In Fruit Flies

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 21°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...