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Drosophila Melanogaster Cross Lab Report

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The Drosophila melanogaster Cross
David Tyer

I. INTRODUCTION
The Drosophila melanogaster is one of genetics most studied organisms. This is due to the Drosophila melanogaster being an excellent model organism. The Drosophila melanogaster has a short lifespan and is genetically similar to humans (Adams 2000). This experiment had three major goals. The first goal of this experiment was to determine which eye colors, body colors and wing type are dominant or recessive. The second goal was to determine if the gene for eye colors, body colors and wing type are on an autosomal or a sex chromosome. The third goal was to determine if eye colors, body colors and wing type are physically linked or independently assorting (Morris and Cahoon). First …show more content…

Also, a mutant (white eyes and without wings) male is crossed with a virgin wild type female (caramel bodies, red eyes and wings that are oval and folded). Both of these crosses are accomplished in an identical method. The mutant males are sedated utilizing an ether-based product known as fly nap. The vial containing the males is laid on its side. Fly nap is applied to a brush and the brush is inserted into the vial housing the mutant males. The brush is allowed to remain in the vial until all males are sedated. Once sedated the males are carefully removed on to a piece of card stock. At which point the males are carefully introduced to the females vial. The males and females allowed to remain for one week for mating. Week two the parental generation must now be removed to not contaminate the F1 generation. While the F1 generation is still in larva state the parental generation must be removed. This is accomplished by again adding the brush vial and allowing for the sedation of the parental generation. Once the parental generation has been removed and discarded the larva are allow to mature. At week three male and female F1 offspring are crossed to produce the F2 generation. This is again accomplished by sedating the F1 generation with fly nap and sorting males and females apart. …show more content…

In this particular case are degree of freedom was 4 making for a P value of 0.05 and a critical value of 7.815. For F1 X F1 (1) the males (O-E)2 /E value was 647.7 and the females (O-E)2 /E value was 6510.4 when compared to the critical value of 7.815 both male and female must be rejected as possible 9:3:3:1 independent assortment. As for F1 X F1 (2) the males (O-E)2 /E value was 104.9 in the female (O-E)2 /E value was 95.1 both male and female must be rejected as possible 9:3:3:1 independent assortment. This experiment was plagued by low survival rates. Meaning data could very easily be skewed from this factor. In fact the F1 X F1 (2) Cross values are relatively close to the critical value in that with better data it is possible the F1 X F1 (2) Cross is indeed 9:3:3:1 independent

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