Drosophila Melanogaster Lab Report

Introduction

Drosophila melanogaster has been studied by scientists for over a decade, since the first use in 1901 by a Harvard group led by William Castle's (Jennings, 2011). The main reason the Drosophila melanogaster was used is the fact that they only have four chromosomes, making the mapping of their DNA more manageable, compared to organisms like humans who have twenty-three chromosomes (Elgin, 2018). Drosophila melanogaster also have short life span and larval phase, can be reasonably easy to sort between by gender, express four different eye colors, and are cheap. The P-generation for this experiment consisted of ten wild type brick red eyed males, and fifteen mutant white eyed females. It is possible for the flies to inherit their

CO2 tanks, as well as CO2 pads, dissecting microscope, pencil, vials/test tubes, fly food, paint brushes or a spatula, a dawn filled cup of death (morgue), and live Drosophila melanogaster will all be necessary. Starting with two vials full of food to sustain the flies/pupa, we began with the parent generation already in the vials in the pupa phase. After all the flies had enclosed, having emerged from the pupa stage into adulthood, we were ready to examine them. Each group turned on their CO2 pads, and prepared to open the test tubes. Placing the test tubes upside down, and tapping the glass to make the remaining flies fall to the CO2 pad. After the flies had been sedated by the CO2, the groups were ready to score the flys. Scoring is the act of separating the flies by eye color, and gender. In this lab we used a paint brush to separate the flies more easily. The end result for the parent generation worked out to be ten wild type males, and fifteen white eyed mutant females. Once the results were recorded, we needed to remove the current generation from the vials into the morgue, this action is called clearing, and serves a vital role in keeping our parent generation from contaminating our F1 generation. Each of the two new vials were labeled with a start date, and a stop date. After a week the test tubes were checked, and it was observed that the previous generation had

For the F1 generation we received no male mutants or females of any kind, but four males expressed the wild type phenotype, and eighteen females expressed the wild type phenotype. The F2 generation yielded very different results from the first. In males, five scarlet eyed mutants, three white eyed mutants, eleven brown eyed mutants, and twenty five wild type males were expressed. For the females in the F2 generation, seven scarlet eyed mutants, one white eyed mutants, eight brown eyed mutants, and thirty-six wild type brick red eyes were