Drosophila Melanogaster - Sex Linkage and Inheritance of Genes Through Cross Breeding

In this experiment we tested to see what the offspring of an unknown cross of an F1 generation would produce. After observing the F2 generation and recording the data we found some of the Drosophila showed mutations, two in particular. The mutations were the apterus wings, and sepia eyes. After collecting our data through observation, a Chi-test was conducted resulting in a Chi-value of 5.1 and a p-value of .2. Since the p-value was greater than 0.05, there was no significant change in the data. This proved that the Drosophila flies still followed the Mendelian genetics of a 9:3:3:1 ratio.

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.

We started out with three populations; B, D, and G. In order for us to properly create controlled genetic crosses, we had to ensure that all the female flies were “virgins”.

The motivation of this lab report is to use Mendel’s Laws of Inheritance to analyze and predict the genotypes and phenotypes of an offspring generation (F2) after knowing the genotypes and phenotypes of the parent generation (F1). The hypothesis for this experiment is that the mode of inheritance for the shaven bristle allele in flies is autosomal recessive in both male and female flies.

The anesthetiser jar containing Vestigial flies was sealed until all flies inside the jar were unconscious

11. The progeny of a Drosophila female (heterozygous at three loci: y, ct, and w) crossed to a wild type male are listed below:

9. Fourth week: Begin removing the F2 flies. Record their sex and the presence or absence of mutation(s). The more F2 flies collected, the more reliable the data will be. You may have to collect flies over a three-or four day period (or more). Try to collect at least 200 flies (probably quite a bit lofty).

Note that the vials must lie horizontally in order to keep the wings from becoming stuck. Each vial was monitored for the next two weeks, and after approximately 10 days, the larvae became dark-colored. This indicates the impending hatching of offspring, so the adults were then removed from the vial. Once the offspring began to hatch, they were also removed, anesthetized, and counted. Virgin females must be removed within 8-10 hours of hatching in order to ensure that they had not mated with the males of the same phenotype.

15) Bring the flies to the morgue (the bowl of isopropyl alcohol) to kill them.

Dobzhansky, T. (1930). The manifold effects of the genes stubble and stubbloid in Drosophila melanogaster. Z. indukt. Abstamm.- u. VererbLehre 54: 427-457.

The F1 offspring of the monohybrid crosses are eventually crossed again, to produce an F2 generation of flies. Monohybrid

What makes D. Melanogaster perfect for the experiment is the two week lifespan and their ability to reproduce in high numbers. While using D. Melanogaster in an experiment like this, reproduction can be manipulated through

Offspring differ somewhat from their parents and from one another. Instructions for development are passed from parents to offspring in thousands of discrete genes, each of which is now known to be a segment of a molecule of DNA. This essay will explore some of the reasons behind how and why these differences in appearance arise, from the base sequence of DNA through to the observed phenotype.

Heredity – the transmission of traits from one generation to another, from parents to offspring; the protoplasmic continuity between parents and offspring