Drosophila Melanogaster Eye Color Study

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 conducted experiment assists in determining an unknown mutant allele found in Drosophila melanogatser. Mutant 489 illustrates a defect in eye pigmentation, which displays a dark brown eye color verses the brick red eyes in wild type flies. Based on the appearance our 489 mutation we've names our mutant rust.

There were eight different phenotypes among the progeny. The highest phenotypic frequency was the w+m+f+ at 40% of the progeny. The lowest was the w+mf+ with only 2 % of the progeny (Table 3). The sum of the recombinant frequencies between genes, table 4, was used to determine the gene distance. The recombinant frequency was determined by counting the number of individuals whose genes differed from that of the parental type. For example, how many individuals white eye gene, and miniature wing gene, differed from both wild-type or both mutants. Recombination occurred between the white and miniature gene 33 times. Recombination occurred between the miniature and the forked genes 31 times. Recombination occurred between the white and forked genes 44 time. Double recombination occurred 10 times. Therefore, genes w and f are 64 m.u. apart, m and w are 33 m.u. apart, and m and f are 31 m.u. apart (Figure

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.

Both males and females are affected with this gene, making it autosomal. This mutation results in a light brown-pigmented eye instead of the red wild type eye. This is due to the lack of pigments in the eye that would normally give rise to the wild type eye color (Lloyd 1998). The eye color darkens when the fly starts to age. Although, this mutation primarily affects the eye color, it also changes other parts of the body. For example, the malphigian tubules are a pale yellow. The fly’s testes and vasa become colorless during their adulthood. A possible chromosomal effect on phenotype occurs when alleles are recessive. When these homozygous recessive alleles are present in a fly, they are

The major topic of this experiment was to examine two different crosses between Drosophila fruit flies and to determine how many flies of each phenotype were produced. Phenotype refers to an individual’s appearance, where as genotype refers to an individual’s genes. The basic law of genetics that was examined in this lab was formulated by a man often times called the “father of genetics,” Gregor Mendel. He determined that individuals have two alternate forms of a gene, referred to as two alleles. An individual can me homozygous dominant (two dominant alleles, AA), homozygous recessive, (two recessive alleles, aa), or heterozygous (one dominant and one recessive

The progeny of this cross were known at the F1 generation. Phenotypes seen in this cross were recorded. Males from this cross were collected. A male that with a different phenotype from the mutation in the mutant flies was selected. (If the mutation in the mutant flies is white-eye, a male without an eye mutation is selected.) The selected male from the F1 generation is then crossed with a virgin female from the parental generation. After which, the phenotypes seen were recorded and used to determine which chromosome the mutation is located on and what the mutation is.

None of the mutants are dominant, so all the mutants are recessive. This can be inferred by examining all the crosses. The data of the crosses yield more of the wild-type flies

We deduced possible modes of inheritances by observing the F1 generation of a pure-bred cross. F1 generation data was used to construct our null hypothesis that the white eyed mutant phenotype is autosomal recessive to the wild type brick red eyes. We then attempted to falsify this hypothesis using a chi-square analysis. We obtained a significant p-value greater than 0.1%, rejecting our null hypothesis, allowing us to accept our alternative hypothesis.

The aim of the di-hybrid cross was to analyse the the body colour trait and the wing type trait in the drosophila, to establish which allele was dominant in each case; either the wild-type or the ebony body colour, and either the

10 first parental flies (10 male and 10 female) were distributed by TA at the first day of the experiment and these were crossed to each other to produce the first generation in a vial. The phenotypes of the male parental flies were combination of 5 red and 5 apricot eye colors, and 10 wild type body color. The phenotypes of the female parental flies were all same and 10 white eye color and 10 ebony body color. The summery of the parental fly phenotype are shown in the following as Table 1. Starting with 20 first parental flies, crossing was continuously carried out until the overall generation reached sixth. While generations go, the phenotypes of each generation was recorded on a score sheet every another week and adult flies were removed from the vial afterward. By doing so a previous generation does not blend in a new generation giving more accurate phenotype count. The students were familiarized to the technique to identify the phenotype of flies previously under dissecting scopes. The identified phenotypes of the flies are: sex, eye color (white, apricot, and red) and body color (wild and ebony). If there was any odd phenotype other than these mentioned, it was also recorded as a possible mutated allele. The italic letters used in this paper represents each allele type. r, wa and w respectively represent red, apricot, and white eye color alleles. w+, e, b, al respectively represent wild type, ebony, black and albino body color alleles. Among these b and al did not exist in the first parental flies. After all the phenotypic data of the flies were collected through six generations, the count data was reorganized in a spread sheet to determine the allele frequency for each allele. The resulting figures were input to a distributed excel sheet to automatically draw a graph for

Intro: In this laboratory experiment we cross bred fruit flies (Drosophila melanogaster) in order to identify which traits were passed onto their offspring. Since the 20th century the common fruit fly has been a useful and one of the best organisms for the study of genetics. Thomas Hunt Morgan was responsible for the work that demonstrated the huge advantages of fruit flies and led to them becoming a common model for scientific research and testing. Its relatively short generation time (~2 weeks) produces a high rate of reproduction and since they are small and easy to grow, they make for a cheap and simple experiment to do in the laboratory. They also only have four pairs of chromosomes which allow being able to detect which traits pass on to their offspring quite easy.

In this experiment documents a white community school of third grade class in Iowa are exercising discrimination based on eye color with two distinct groups, the blue eyes and brown eyes. The purpose of the experiment if children can understanding of discrimination. The Teacher decided to divide the class by different eye color the blue-eyed and brown-eyed students. On the first day the blue-eyed students are praised more than the brown-eyed students. They’re reward were to get extra recess hours, they can drink from the fountain, get seconds for lunch, and play on the playground. The brow-eyed students were not privileged to do this activity. The second day the teacher switched the roles that the brown-eyed students are praised more than the

Based upon observation of the F1 generation, we hypothesize that the inheritance of the white-eye (W) mutation is sex-linked and recessive wild type.

If we take S to represent the straight winged insects and a dominant gene and c to represent the curved winged insects. Then you use a punnet square or a test cross. As long as you have the genotypes of the parents then you are good to go. If the alleles of the fly are Sc, then they are heterozygous if its SS then they are homozygous.