Drosphila Experiment Lab Report

Drosophila melanogaster is a small, common fly found near unripe and rotted fruit. It has been in use for over a century to study genetics. Thomas Hunt Morgan was the best biologist studying Drosophila early in the 1900’s. Morgan was the first to discover sex-linkage and genetic recombination, which placed the small fly in the forefront of genetic research. Scientists have used Drosophila for many reasons. For one they are very easy to maintain, breed, anesthetize, and kill with little equipment. They are also very small and it is easy to distinguish males vs females and sexually mature flies and virgins. At lastly, the flies have a very short two week life span. On days 2-7 of their life

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.

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.

It would be expected that the mutant F1 flies would be heterozygous for the allele responsible for the grounded trait. If two F1 flies were mated, the percentage of flies that would be expected to be wildtype in the F2 generation would be 25% mutants given that the mutant allele (ap) is predicted to be recessive and, leaving 75% to be wildtype (ap+).

When the larvae hatched, the anesthetising procedure shown from steps 1-5 was used to record the phenotype of the F1 generation and number of male or female flies.

Purpose The purpose of this experiment is to determine whether the fruit flies were dominant/recessive or linked/non-linked. The traits I chose for this activity was the fruit fly with vestigial wings and purple eyes, the other fruit fly I chose was a normal fly, also called wild type. While writing out my plan for this activity I thought it would be interesting to test a female mutant and the wild type male, the ratios I came up for this experiment was 2:2 and the mutant allele being recessive to the wild type. In this case, the words recessive and dominant means, if the child born from the parents inherits more of the genes and traits from let us say the father then the alleles of the father is dominant over the mother’s genes.

Genes can either be sex-linked or autosomal. If a gene appears mostly in one sex chances are the gene is sex-linked and if it appears frequently in both sexes it is most likely autosomal. Using Drosophila melanogaster, also known as the fruit fly, we will determine whether the gene is sex-linked or autosomal. Drosophila melanogasters have a relatively short life span and are an excellent organism for genetic studies because it has simple food requirements, occupies little space, is hardy, completes its life cycle in about 12 days at room temperature, produces large numbers of offspring, can be immobilized readily for examination and

The materials and methods are adapted from Evolution Lab Manual, Lab One: The Fly Lab (Welsh, 2016). The stock bottles contained true breeding homozygous flies of either ebony body or wild-type body (tan). The fruit fly was observed because it is easily cultured, it has a two week generation time at 21-23°C, it occupies little storage space, and it is large enough to see phenotypic traits. Two cultures were set up with an equal number of flies with each trait, to start with an initial allele frequency of p=0.5.

Heterozygotes, which have the wild type phenotype, have normal sight which gives them the advantage of finding a mate and have a better success with attracting a mate with their courtship song (Kyriacou et al, 1978). The male heterozygous Drosophila had a better advantage at mating than the homozygotes, which were the ebony, and therefore we predict there will be more wild type by the end of the experiment.

The vials were separated into males and females. Five male and female from each vial were put in a specific vial ending up with 20 flies in one vial. It was made sure the group had enough flies; any extra flies were distributed among the groups to assure everyone has the correct amount of flies for each genotype. The exact number of flies for all four phenotypes ( male (+/+), male (e,e), females (+,+), and female (e,e)) were used. Any remaining flies not need by anyone were put cake into the cultured vial where they came from.

we said goodbye and placed them in the fly morgue. We allowed the F2 larval

The adult flies then emerge from the pupae. (This whole cycle is known as complete metamorphosis.) The adults live from half a month to a month in the wild, or longer in benign laboratory conditions.

Looking at the lateral view, there are eyes texture difference between the wild type and mutant D. melanogaster. On the wild type, the female fly has dark red eyes color (1B). The pseudo-pupil, a dark spot locates on the center of the fly’s eyes, appear visible to any wild type (1D). The mutant female fly, though has the same eye color as the wild type, but its eyes appear sparkling and has a rough texture (1A). More specifically, the pseudo-pupils are absence to all mutants which contributed to their secondary phenotypic difference to the wild types (1C). Besides that, they both look identical with their body size, bristles, abdomens and wings. There are no missing bristles on the mutant’s thoracic and head; their bristle’s thickness and length

This experiment looks at the relationship between genes, generations of a population and if genes are carried from one generation to another. By studying Drosophila melanogaster, starting with a parent group we crossed a variety of flies and observe the characteristics of the F1 generation. We then concluded that sex-linked genes and autosomal genes could indeed be traced through from the parent generation to the F1 generation.