Chi-Square Test 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

In this experiment, vestigial flies as well as wild type flies were used to create some diversity as well as test one of our hypotheses. Our hypotheses are as follows; 1) The wild type flies will have a greater relative fitness compared to the vestigial flies based on only sexual selection.  The wild type has a relative fitness of 1 since it has fully functional wings.  Vestigial Winged flies are not as sexually appealing since their wings are not functional and the wing movement is a vital part of their mating ritual.  2) The vestigial fly will have a greater relative fitness when considering both sexual and natural selection. With the presence of

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.

In our experiment, we created three crosses; DxG,BxD, and BxG. In crosses BxG and BxD we found a rare mutant fly. This unusual mutant had a misshapen abdomen, deformed wings, and was pale in color. While the mutant was rare, due to the fact that it popped up in both those populations, we hypothesized that this genetic mutant had already previously been discovered and named.

The expected number of wild type flies in the F2 generation is 734.25 and the expected number of shaven bristle flies in the F2 generation is 244.75. This, again, exhibits a 3:1 ratio of normal phenotype to affected phenotype.

Describe the sex and phenotype of the mutant fly. Describe the phenotype as it compares to the wild type.

Genetics can help answer questions about our traits and why we look different and advance in different ways from each other in the world. Chapter 1 explains the basics about how genes work, and the portrayal of DNA and RNA. Chapter 2 describes RNA more in detail and it consist of the explanation of the human genome. Specifically, Chapter 3 clarifies how evolution works and how it relates to genetic and medical research. Furthermore, Chapter 4 and 5 explains the knowledge researchers have about genes role in health and diseases, and how society is affected with the advances in medicine and science given approximate credit to these researchers.

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

Introduction Have you ever wondered how specific traits are passed down from generation to generation? Or if you already know the answer to that question, then how can you determine which traits are dominant and recessive. Finding both answers can be obtained by studying genetics. Reading about these topics only gives you a grasp on how traits work. In a laboratory setting, the answers can be found in an experiment using an unlikely specimen, known as the common fruit fly and its scientific name, Drosophila Melanogaster.

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

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.

The F2 Drosophila produced from crossing the wild-type offspring of the parental cross wild-type males and no-winged females. The F2 generation consisted of 38 wild-type females and 35 wild-type males, totaling 73 Drosophila. There were also 16 no-winged females and 11 no-winged males, totaling 27 Drosophila. Therefore, the total number of Drosophila counted was 100. The phenotypic ratio was 3:1, wild-type: mutant. If the mutation were autosomal recessive the F2 generation’s hypothesized phenotypic ratio would be 3:1, wild-type: mutant. If the mutation were autosomal dominant the F2 generation’s hypothesized phenotypic ratio would be 1:3, wild-type: mutant. The expected ratio for the F2 generation was 3:1, wild-type: mutant. When chi-square

First step, one of the major issues was that all members in the group did not pay attention to the gender of flies in each vial of the unknown P cross of the F1 generation. The number of male and female might not equal to ratio 1:1 in each vial which led to have an error because Bar eye mutation is a dominant X- linked gene that does not assort independently while vestigial wing mutation is autosomal mutation located on chromosome number 2. As a result, vestigial gene assorts independently and does not play significant role with gender in the next generation: however, gender played significant role when determining mutation specifically for Bar eye mutation. Second, there was no differences in the traits as flies observed in first count on April 10 and second count on April 17. Third, there was a difficulty while transferring flies from the vails to the nap chamber. Flies in some vials remained sticking in the food gel due to knocking issue. Some vials accidently knocking aggressively made the flies stick in the food gel. Also, some fruit flies flied and some of them killed accidently while putting the stopper because transferring the flies were quickly from the vials to the nap chamber. Growth condition were not good for some vials that made the group to discard some vials and used the backup vials due to contamination and bacterial infection that killed the flies in some vials. Finally, according to table 4, the individual Chi square for vial A, C, and D was lower than the critical value and support the hypothesis; however, Vial E showed Chi square value greater than the critical value which rejected the hypothesis. Vial E during the second count was not knocked to get the flies away from the stopper which made some of them to fly while transferring them to the nap

In most kitchens the small flies that are found are Drosophila Melanogaster also called fruit fly. They are often brought in by ripened tomatoes, grapes and other perishable items from the garden. Drosophila melanogaster is a little two winged insect about 3mm long two winged insect that belongs to the Diptera, the order of the flies. The drosophila egg is about half a millimeter long. Fertilization takes about one day the embryo to develop and hatch into a worm-like larva. The larva eats and grows continuously, after two days as a third in star larva; it moults one more time to form an immobile pupa. Over the next four days, the body is completely remodeled to give the adult winged form, which then hatches from the pupal

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.