In addition to wild-type flies, 29 different mutations of the common fruit fly, Drosophila melanogaster, are included in FlyLab. The 29 mutations are actual known mutations in Drosophila. These mutations create phenotypic changes in bristle shape, body color, antennae shape, eye color, eye shape, wing size, wing shape, wing vein structure, and wing angle. For the purposes of the simulation, genetic inheritance in FlyLab follows Mendelian principles of complete dominance. Examples of incomplete dominance are not demonstrated with this simulation. A table of the mutant phenotypes available in FlyLab can be viewed by clicking on the Genetic Abbreviations tab which appears at the top of the FlyLab homepage. When you select a particular phenotype, you are not provided with any information about the dominance or recessiveness of each mutation. FlyLab will select a fly that is homozygous for the particular mutation that you choose, unless a mutation is lethal in the homozygous condition in which case the fly chosen will be heterozygous. Two of your challenges will be to determine the zygosity of each fly in your cross and to determine the effects of each allele by analyzing the offspring from your…
25.) When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?…
1. In fruit flies, long wings are dominant to short wings. Complete a cross between a short winged male and a heterozygous female.…
In the reciprocal cross, the behavioural phenotypes were isolated from one another while the wing veins were kept constant (in this case both wild type). When the wild type mellow female Drosophila and wild type hyper male Drosophila were crossed, all female offspring obtained a similar phenotype to that of the male parental while all the male offspring had phenotypical combinations similar to that of the female parent. This set of results shows that the mellow behavioral phenotype is a recessive x-linked gene carried by the female because the resulting male offspring showed the same characteristics to that of the female parent (received X – chromosome from female parent). On an additional note, there was a higher frequency of females in comparison to men; 121 and 105 respectively. In addition, the behavioral gene is sex -linked also because of the different resulting phenotypical ratio in comparison to the cross carried out in vial one.…
This experiment was conducted to study the relative fitness of two phenotypes of the Drosophila melanogaster and how fitness can affect evolution in the population. The phenotypes were placed in two different environments, one in which contained a predator and another with no predator. Results of the experiment would show how the fitness of each phenotype is affected by providing a mechanism, and if evolution was occurring in the population. Two hypotheses were inferred, one for each environment. For the cage uninfluenced by a predator, we hypothesized that evolution would occur due to sexual selection, and that sexual selection would be in favor of the wild-type drosophila. For the cage containing the predator, we hypothesized that the vestigial flies would have a higher relative fitness due to natural selection. A ratio of wild-type to vestigial flies was determined, and was set up in each environment. 10 wild-type to 40 vestigial flies was chosen, giving a total of 50 flies for each environment. Each week the flies were fed, and every two weeks they were counted to represent a new generation. At the end of the 13 week experiment, the last generation of flies were counted and recorded in a data table. The results of the experiment show that evolution was occurring in both cages, and that wild type flies were dominant regardless of the environment.…
Before one can begin the lab, he/she must make a prediction about what gene the trait one are analyzing is on. The trait can either be sex-linked, or autosomal.…
This lab was the study of monohybrid as well as dihybrid crosses. A monohybrid cross is the study of a certain trait whereas a dihybrid cross is the study of the mating experiment between two organisms that are identically hybrid for two traits. ( Reference 1 ) This lab was done to determine the genetic mutations after each generation and to observe the ratios. As each generation of fruit flies came to existence, traits would either be different from each fly or certain traits would disappear from existence. The expected ratio for a monohybrid cross was 3:1 and 9:3:3:1 for the dihybrid cross. For the monohybrid cross, eye color was observed to be wildtype, dark red, or white eyed, which was x-linked. (Reference 2) As for the dihybrid cross, both wing shape as well as eye color was observed. The wings were either straight, wildtype, or shriveled, vestigial, depending on…
Fruit flies have made a huge contribution towards knowledge about genetics, but for most people, they are just annoying insects that are attracted to their fruit. Their scientific name is Drosophila melanogaster, and to scientists, they have been a key to understand many principles of heredity including sex linked inheritance, epistasis, multiple alleles, and gene mapping. Fruit flies were the first organisms to be used for genetic analysis in 1910 by Thomas Hunt Morgan, and ever since, they have been used for genetic experiments (Ashburner).…
In this lab a study of fruit fly genetics was done these creature are readily used for genetic studies .they are easy to maintain. And the females lay a lot off eggs which develop in about two weeks. Fruit fly’s have for distinct stages, the egg, larva, pupa and adult. the egg and larva stages last for eight days, the pupal stage last for six days and then the adult stage which last for many weeks this period of growth is called instars. In this lab a dihybrid cross was performed to get data results and to draw a conclusion to the hypothesis.…
Material: In this experiment, the we used: tape, 2 water bottles, scissors, 6 different cotton balls, 1 chamber, about 20 fruit flies, water, lime water, banana, vanilla extract, and ammonia.…
They thought Mendel’s hereditary determinants were on a locus. They found out that the physical separation of alleles during anaphase I of meiosis accounts for Mendel’s principle of segregation. If the alleles for different genes are located on different chromosomes, they assort independently from one another in meiosis I. This confirmed the principle of independent assortment. Later on, the two scientists came up with the chromosome theory of inheritance, which states that independent assortment happens in metaphase and anaphase of meiosis I. To test the theory of inheritance, scientist Thomas Hunt Morgan used the fruit fly. At one point, Morgan noticed that a male fruit fly had white eyes rather than the wild type red eyes. He concluded that the white eyes resulted from a mutation. He mated a red-eyed female with a mutant white-eyed male and the results showed that all of the F_1 females had red eyes, but the F_1 males had white eyes. This was very peculiar because Mendel already proved that traits are not sex based. Morgan realized that the X chromosome in males and females explained his results. He determined that eye color is carried on the X chromosome and not on the Y chromosome. This is described as sex-linked inheritance. According to the X-linkage hypothesis, a female has two copies of the eye color gene because they have the two X chromosomes, whereas the male fruit flies have the one X chromosome that codes for eye color. The reciprocal cross of pea plants happened on non-sex chromosomes called autosomes. Genes on non-sex chromosomes show autosomal inheritance. Biologists now know that Boveri’s and Sutton's chromosome theory of inheritance was…
In this experiment, the species Drosophila melanogaster, the common fruit fly, was studied to examine the processes of natural selection and genetic drift in the laboratory. The fruit fly has a sex linked gene determining eye colour. Located on the X chromosome, a fruit fly can exhibit the phenotype white eye (homozygous recessive), or red eyed wild-type (dominant). Males of the species are XY, and as such only carry one eye colour determining X chromosome. Females are XX, and can therefore carry two eye colour determining genes. A heterozygous female will always display the dominant wild-type gene if present. The uncertainty of female genotype is cleared by the acquisition of an F0 stock which is homozygous dominant or recessive.…
Famers and herders have been selectively breeding their plans and animals to produce more useful hybrids for thousands of years. It was somewhat of a hit or miss process since the actual mechanisms governing inheritance were unknown. Knowledge of these genetic mechanisms finally came as a result of careful laboratory breeding experiments carried out over the last century and a half. A contributing geneticist named Gregor Mendel (1822-1884), discovered through his research the basic underlying principles of heredity that also applied to humans and other animals. Mendel discovered that certain traits show up in offspring without any blending of parent traits. This observation that these parental traits do not show up in offspring plants with intermediate forms was critically important because the leading theory in biology at the time was that inherited traits blend from generation to generation.…
Looking at all of the fruit flies, there is no possible way for the parent flies to be homozygous. If the parent flies were homozygous, both the F1 and the F2 phenotypes would be the same holding a 1:1ratio, instead of the 9:3:3:1 ratio that was observed. The purpose of this experiment was to determine the F1 genotype of fruit fly traits using the phenotypic ratio of the F2 generation and to express these results of the unknown cross through a Chi-square model. After taking data with the Chi-squared value of 5.64, the degrees of freedom were 3 and the p-value was between .05 and .2, it is confident to fail to reject the null hypothesis, which leads the experimenters to believe that the observed phenotypic ratio does significantly deviate from that expected under the assumption of Mendelian inheritance. In the future, exploring more complex animals other than fruit flies, such as mammals or reptiles, would make this experiment a little more difficult, but more interesting as well. Without Mendelian genetics, it would be much more difficult to predict traits in organisms across the living…
In my testings with breeding the fruit flies, I learned that the purpose of breeding them was to test how genetics pass from generation to generation, also known as heredity. We attempted to breed the flies and get them as close to a 9:3:3:1 ratio as possible. This would lead to an acceptable trait ratio. My hypothesis was that if we were to breed the flies in a stable environment, the most common fly (or the fly with the highest population) would be the red eyed, winged flies.…