Mendelian Genetics of Drosophila | Lab Report

Mendelian Genetics of Drosophila | Lab Report Joshua Park Introduction Drosophila melanogaster, known generally as a fruit fly, is a cost-effective model organism with certain qualities that make it an ideal research tool in various fields of science. Drosophila melanogaster are preferred over vertebrate models as a research tool in genetic studies due to its basic food requirements, its ability to produce large numbers of progeny in a short period of time, and quick life cycle. Depending on diet and stress its life span ranges up to an average maximum of 120 days. They are also easy and inexpensive to culture in a laboratory environment, not to mention they take up very little space. In addition, they have diverse phenotypic traits that are easily observable. Its anatomical features like the compound eye allow easy access for phenotypic characterization. They also have abundant genetic variation in a relatively small genome. Approximately 13,600 protein-coding genes are located in only four chromosomes. Many heredity variations can be studied in these flies.An example of this is the gene that codes for eye color in Drosophila, which can result in red, sepia, white, or brown phenotypes. This unique ability to generate many different phenotypes provides D. melanogaster its practicality as an effective research tool for the study of the relationship between genotype and phenotype. In this experiment, we wanted to understand which phenotypic results would result from a mating cross between D. melanogaster parents with certain wild type and mutant phenotypes for eye color and wing size. The wild type phenotype for eye color is red, while the mutant phenotypes are sepia and white. The wild type phenotype for wing size is long, while the mutant phenotype is apterous, or no wing. We also wanted to know the reason for such phenotypic ratios, which we hypothesized to be the Mendelian Law of Segregation in regards to the study of one trait. To do this, we mated D. melanogaster flies with similar and different phenotypes in order to see how well our results agreed with the Mendelian Law of Segregation. We created two crosses: a monohybrid cross where both male and female flies had the wild type phenotype (Bb and Bb), and a monohybrid cross where the male flies had the mutant phenotype (XwY) and the female flies had the wild type phenotype (X+X+). For our first monohybr id cross, we wanted to know what the expected phenotypic ratio would be when crossing wildtype red-eyed flies, according to Mendels first law. We hypothesized that the expected phenotypic ratio for a cross with red-eyed flies would be 3:1 because according to the Mendelian Law of Segregation, the two alleles are separated from each other during gamete formation. For our other monohybrid cross, we wanted to know what the expected phenotypic ratio would be when crossing wildtype red-eyed flies with mutant white-eyed flies, once again according to Mendels first law. We hypothesized that the expected phenotypic ratio would be 1:1 due to the Mendelian Law of Segregation. Using the chi-square test, we will be prepared to reject or fail to reject our hypothesis according to our mating cross results. Title: Mendelian Genetics of Drosophila Material and Methods Students in groups of two were given a number corresponding to a specific fly stock vial. Two culture vials pre-filled with food and cotton plugs were collected at the front of the classroom. The group number and initials were written on the vials. Next, the assigned stock vials were obtained and were lightly tapped on the lab bench to remove the flies from the cotton plug. An anesthesia wand was dipped into the FlyNap and carefully inserted through the cotton plugs into each stock vial. The stock vials were immediately placed horizontally on the lab bench after, preventing the flies from drowning in the food media. After waiting a few minutes for the flies to fall asleep, the wands were removed from the vials and the flies from each vial were dumped onto separate index cards. The flies were observed under a dissecting scope and found to be either male or female based on the body morphology. A lamp light was used for an easier inspection. Using a brush, 5 male and female flies from e ach cross set were transferred to the culture vials. Once again, the vials were made sure to be placed horizontally on the lab bench. Each culture vial was sealed with a cotton plug, and the leftover flies were returned to the stock vials. The vials were returned to the TA for storage. Once larva could be seen in the fly culture vials, the parent flies were put to sleep and removed from the vials to avoid backcrossing. Once it was evident that many F1 offspring had matured into adults, the flies were put to sleep and dumped onto notecards. The flies from the assigned cross set were observed under a dissecting microscope, and the eye color and wing presence was recorded for each fly. For cross set E, both the sex and phenotype for each fly was recorded. After every F1 generation fly was counted for each cross set, they were dumped into the morgue. Results Cross Set: C Table 1: F1 phenotypes for cross set C Phenotype Total number Eye color Wing size Red Long 39 Sepia Long 9 The F1 data that was collected for cross set C is indicated in Table 1. The number of flies for each phenotype is shown. Figure 1: Graphical representation of F1 data for cross set C Figure 1 presents the data from Table 1 in the form of a bar graph. According to this data, there were more flies with wildtype red eyes (39) compared to flies with sepia eyes (9). There was a total of 48 flies for cross set C. Cross Set: E Table 2: F1 phenotypes and sex for cross set E       Phenotype Number of Male Flies Number of Female Flies Total number Eye color Wing size Red Long 10 9 19 White Long 10 13 23 The F1 data that was collected for cross set E is indicated in Table 2. The number of flies for each phenotype and sex is shown. Figure 2: Graphical representation of F1 data for cross set E Figure 2 presents the data from Table 2 in the form of a bar graph. According to this data, the number of male flies with wildtype red eyes (10) was equal to the number of male flies with white eyes (10). In addition, the number of female flies with wildtype red eyes (9) was very similar to the number of female flies with white eyes (13). There was a total of 42 flies for cross set E. Phenotype Observed Number (O) Expected Number (E) Deviation (O E) (O E) ² (O E) ²/E Red eyes/long wings 39 36 3 9 0.25 Sepia eye/long wings 9 12 -3 9 0.75 Total 48 48 X ² = 1.00 Chi-Square Analysis: Table 3:Chi-square analysis for cross set C Cross Set C:   à Ã¢â‚¬ ¡2 = Degrees of freedom (df) = 1 p-value range = 0.1 Table 4: Chi-square analysis for cross set E Phenotype Observed Number (O) Expected Number (E) Deviation (O E) (O E) ² (O E) ²/E Red eyes/long wings 19 21 -3 9 0.429 White eyes/long wings 23 21 2 4 0.190 Total 42 42 X ² = 0.619 Cross Set E:   à Ã¢â‚¬ ¡2 = Degrees of freedom (df) = 1 p-value range = 0.1 The chi-square analysis was completed for both crosses to compare the observed results with the expected results. The p-value for cross set C was between 0.1 and 0.9. The p-value for cross set E was also between 0.1 and 0.9. As a result, we fail to reject the null hypothesis of the chi-square test for both crosses. Discussion According to the results of this experiment, our research hypothesis was supported in each mating cross. We hypothesized that the expected phenotypic ratio for a cross with red-eyed wildtype flies would be 3:1, because according to the Mendelian Law of Segregation, the two alleles are separated from each other during gamete formation. Cross set C produced about three times as many red-eyed wildtype flies compared to sepia-eyed flies, confirming our hypothesis. For our other monohybrid cross, we wanted to know what the expected phenotypic ratio would be when crossing wildtype red-eyed flies with mutant white-eyed flies. We hypothesized that the expected phenotypic ratio would be 1:1 due to the Mendelian Law of Segregation. Cross set E produced equal amounts of red-eyed flies and white-eyed flies, confirming our hypothesis. The ratios obtained for cross sets C and E accurately reflected the expected results for a monohybrid cross and test cross respectively, as claimed by Mendels law o f segregation. The results of the chi-square analysis show that the observed counts were very close to the expected counts. The p-values for both cross sets C and E were between 0.1 and 0.9. Since these p-values were larger than 0.05, it was concluded that we should fail to reject the null hypothesis. Failing to reject the null hypothesis means that the observed data was not statistically different from the expected data. The mode of inheritance for cross set C was determined to be complete dominance. In complete dominance, the dominant allele completely masks the effect of the recessive allele when both are present. Since both parents were found to be heterozygous for eye color (Bb), the dominant red allele masked the effect of the recessive sepia allele. The F1 data for cross set C demonstrates that wild type red eyes are dominant over sepia eyes, since the ratio of red-eyed flies (BB or Bb) to sepia-eyed flies (bb) was calculated to be 3:1, as expected for a monohybrid cross according to Mendels law of segregation. The mode of inheritance for cross set E was determined to be X-linked. Genetic conditions with an X-linked recessive inheritance pattern usually affect only the males in a family. This is because they are caused by altered or mutant genes found on the X-chromosome. Females are born with two X-chromosomes, so the effects of a working gene on one can mask the effects of a mutant gene on the other, which is similar to complete dominance. They will normally be unaffected carriers of the condition. Males have only one X-chromosome, so if they inherit one with a mutant gene (XwY), they will be affected. The F1 data for cross set E demonstrates that the traits for red eyes and white eyes are located on the sex chromosome, since the ratio of red-eyed flies to white-eyed flies was determined to be 1:1. This indicated that the red-eyed female flies were heterozygous for eye color (X+Xw), since the contribution of a mutant allele from both parent flies would result in offspring with red eyes an d white eyes in equal proportions. These results are comparable to the data from Thomas Hunt Morgans experiment with D. melanogaster. In his experiment, he discovered a mutant gene affecting eye color. This mutant gene was expressed as a white color in the eyes. Morgan proceeded to discover that the gene for eye color was inherited in different ways depending on the sex of the fly. This difference came from the fact that female flies have two X chromosomes, while male flies only have one X chromosome and a Y chromosome. Morgan found that this gene had a similar inheritance pattern to the X chromosome. Thus, Morgan concluded that this gene was X-linked. A limitation of this experiment is the fact that we only counted progeny during one session. Multiple trials of counting offspring may have produced closer values to the expected ratios of Mendels law of segregation. Another limitation would be the difficulty of identifying male flies from female flies in a quick and efficient manner. This research has demonstrated the practicality and versatility of D. melanogaster as a tool for research in the lab. Although these fruit flies may seem like very simple and insignificant organisms, they allow us to do research that may otherwise not have been possible. I plan to conduct further studies with D. melanogaster in the field of pharmacology. Since humans share key physiological processes with this organism, D. melanogaster would serve as an effective model for drug discovery. I aim to generate a new drug compound that would greatly aid in the treatment of type 2 diabetes. I hope that the research conducted with these flies will allow for greater discoveries in various fields of science that will contribute to the advancement of mankind. References Jennings, B. H. (2011). Drosophila a versatile model in biology medicine. Materials Today,  14(5), 190-195. doi:10.1016/s1369-7021(11)70113-4 Morgan, T. H. (1910). Sex Limited Inheritance In Drosophila. Science, 32(812), 120-122.  doi:10.1126/science.32.812.120 Pandey, U. B., Nichols, C. D. (2011). Human Disease Models in Drosophila melanogaster and  the Role of the Fly in Therapeutic Drug Discovery. Pharmacological Reviews, 63(2),  411-436. http://doi.org/10.1124/pr.110.003293 Prà ¼ÃƒÅ¸ing, K., Voigt, A., Schulz, J. B. (2013). Drosophila melanogaster as a model organism for  Alzheimers disease. Molecular Neurodegeneration, 8, 35. http://doi.org/10.1186/1750-1326-8-35     Ã‚   Plagiarism: Types, Causes and Effects Plagiarism: Types, Causes and Effects KENNEDY MULI KAILITI PLAGIARISM Introduction Plagiarism is ideological theft. When a person takes and idea that is not their own and represents it for credit. This is a false representation of oneself by using work or an idea that is not original or stolen from another person. Furthermore different constituencies have different meaning for the history of plagiarism. We might helpfully regard it as a triple entity or triangle. At one point of the triangle is cheating involving written works, the second inadvertent a failure to master conventions and the third are professionals who another work without permission for their own benefit.[1] This is just taking advantage of other peoples creativity without acknowledging them. Plagiarism represents truth without representing the source of the truth so ultimately it becomes its truth from the wrong person. When plagiarism is done without intention, knowledge or as a mistake then its called miss-use of sources. The great controversy on plagiarism is drawing the thin line between the de liberate and mistake and who takes responsibility between the teacher and the student. Plagiarism has been there as long as man existed and there was art and creativity but the realization of the vice and its consequences could have come with the printing press and academic advancement. In the early years of human existence philosophy, music and poetry were the ideologies and their practice as a sign of civilization and social advancement. The mode of education was informal and there was not based on research and writing and though plagiarism was practiced there is no data on who and when it started. In the definition and practice plagiarism was practiced as long as man lived. As people put their ideas and creativity in writing, distribution, business and credit then plagiarism became a parallel business. The publishing and printing companies and the authors had to protect themselves from theft and so the copy right protection laws. The twentieth century has come with innovation, scientific discoveries and research and plagiarism has risen as a competing factor. There is need to protect individual work and publishers from those who plagiarize to avoid the gains achieved so far and chaos and confusion. The world has turned to capitalism and competition for resources and fame. Plagiarism has become more alive in this century and its a moral and legal matter that is challenging every society. The academic world has been transformed to research and analysis and students excel only after writing essays, papers, thesis and publication making plagiarism a great threat. The new form of plagiarism is not for economic and popularity gain but for academic success and it a vice in all learning institutions. There has been so many ideas presented in all academic fields and with technological advancement plagiarism is easy and appealing today than before. There is no limit to the destruction that plagiarism has done economically, politically, socially, emotionally and often leads to enemity, wars and legal disputes. Today in music and art industry plagiarism is a quick fix to fame and riches. Time as a resource today is more precious than ever and people are willing to take shortcuts and achiev e goals within a short time. There is a lot involved in research, organization and tests in order to present work that is credit worthy in all fields of life so there is a trend to take shortcuts. Today there is unwritten policy of publish or perish in universities and so lecturers are likely to redo an old idea thus self -plagiarism. The internet has come of age and information is available all over the web for all disciplines and this is enticing to those who want to plagiarize. There is a demand for innovation, art, music, news and economic benefits are too good attracting the real and fake at the same time. Types of Plagiarism Plagiarism can either be intentional or accidental but the form and modes it takes vary a lot based on the situation. There is concern about academic plagiarism but there is a wide range from the unknown to the known , the written and the spoken and just like theft its trends and forms has no limits. The common one in research are taking some presented idea from a pool of knowledge and presenting it for credit. When one recycles and old concept or idea its self- plagiarism and the copy paste computer technology is a monster that propagates plagiarism. There is a pool of knowledge in all fields and research is ongoing in all parts of the world so plagiarism can arise unknowingly when there is agreement on the same concept and ideology. 14 Seven sons of a Jewish high priest named Sceva were doing this.15 But the evil spirit answered them, Jesus I know, and Paul I recognize, but who are you? 16 And the man in whom was the evil spirit leaped on them, mastered all of them and overpowered them, so that they fled out of that house naked and wounded.[2] This is spiritual plagiarism as people assume the position of Paul and Jesus. Percentage of College Students Admitting to Selected Cheating Behaviors, 1963 and 1993[3] Tests/Examinations 1963 1993 Copied from another student 26% 52% Helped another student cheat 23% 37% Used crib notes 16 % 27% Written Work Copied material without footnoting 49% 54% Plagiarized 30% 26% Falsified a bibliography 38% 29% Turned in work done by another 29% 14% Collaborated on assignments requiring individual work 11% 49% The use of plagiarism has been on the rise just and taking new modes. This research data information show that the percentages have almost doubled in the thirty years. This trend means that in the next century plagiarism will be at level institutions and schools will find overwhelming. There is a great danger for academic and research advancement from plagiarism and there is a wake -up call. The reason for this paper This paper is to demonstrate that I have a clear knowledge of plagiarism and Calvin Theological Seminary rule on plagiarism. I posted this in my paper as a case study and after using the name of the person publishing this information I assumed this is not taking credit or plagiarism. I pledge i will not plagiarize again and action will be taken against me in future as per Calvin Theological Seminary statutes on plagiarism. Max Brewer in his 1907 book Der Deutsche Christus (The German Christ) During the First and Second World Wars, German Protestant leaders used the writings of Luther to support the cause of German nationalism On the 450th anniversary of Luthers birth, which fell only a few months after the Nazi Party began its seizure of power in 1933, celebrations were conducted on a large scale by both the Protestant Churches and the Nazi Party. .At a celebration in Kà ¶nigsberg, Erich Koch, at that time the Gauleiter of East Prussia, made a speech in which he, among other things, compared Adolf Hitler with Martin Luther and claimed that the Nazis fought with Luthers spirit. Such a speech might be dismissed as mere propaganda, but, as Steigmann-Gall points out: Contemporaries regarded Koch as a bona fide Christian who had attained his position [as the elected president of a provincial Church synod] through a genuine commitment to Protestantism and its institutions. Even so, Steigmann-Gall states that the Nazis were not a Christian movement. The prominent Protestant theologian Karl Barth, in1939 stated that the writings of Martin Luther were used by the Nazis to glorify both the State and state absolutism: The German people suffer under his error of the relationship between the law and the bible, between secular and spiritual power, in which Luther divided the temporal State from the inward state, focusing instead on spiritual matters, thus limiting the ability of the individual or the church to question the actions of the State, which was seen as a God-ordained instrument. Effects of plagiarism Plagiarism affects the individual and the society and the effects can be long lasting and devastating. The person involved will lose trustworthy, moral, academic and social standing. This becomes worse when the person is taken to court or loose license of practice and financial loses. Those in the schools are expelled and many years of study and research go to waste. Plagiarism affects just like theft can be too cruel with years of suffering and regret. In the world today there are people that have lost positions of power and authority and careers destroyed. In the society plagiarism can result to financial loses and as companies and jobs are affected, court cases and warring parties, and threatening social standing. Reasons for plagiarism Ignorance and carelessness is the major sources of plagiarism. Ignorance and carelessness are also the major sources of the excuse from students who are caught plagiarizing. Even in cases where there are established writers, politicians, and academics have been caught plagiarizing the most common reason is confusion in my notes.[4] There is always a reason behind every action good or bad and so people have different reasons to justify plagiarism. The world living in the era of quick fix and people have no time to invest in hard work as time becomes the most valuable resource. A majority of the plagiarism is intentional and by people that are well vast in their fields of knowledge but have little time to carry out a research. The financial and positional gain is attractive and is its good luck adventure that usually goes bad and becomes destructive. There is all information in the Web about anything and this makes plagiarism the easy and quick path to take. The economic trends today h ave forced people to do extra work , juggle between multiple careers , become student workers and so there is little time to invest in school and learning hence plagiarism is a solution. Self-plagiarism is one that can be done unaware after years of publishing and at times its miss-understanding and mistakes of not doing a citation. When people do research and writing they do it without fore knowledge of other people involved in the same work so plagiarism out of ignorance may not justify judgement and condemnation. There is a blame and counter by teachers and students but the bottom line is plagiarism is plagiarism. Today learning is intensive and cumbersome and most students had find it hard to match the pace and hence plagiarism. Conclusion Although we are teaching academic writing we cannot discount the cultural context. It invigorates the writing because is connected to the writers identity informing the writers voice -and yes it can be incorporated in to academic writing. Free writing should allow cultural context to serve as the true and comfortable setting in which second language students could get started in the process of writing a personal essay or research paper. [5] When people do research and writing they do it in their character and nature and the work cannot be separate from themselves. All people live and work in communities that influence their thinking and actions and so when writing in their true self their work will be more original. When writing from second language and culture, under strict guidelines and limits and the objective of teaching and learning is defeated by just fulfilling the purpose. There is a reason to demystify plagiarism by teaching students those engaging in research and writing a bout it, and the basic academic law of education is character. There is need for continuous and genuine conversation by all institutions on the standards, punishment, and modes of plagiarism as new method and techniques evolve with technological advancement. Schools and universities need to engage parents and guardians since plagiarism is vice that is academic and moral. The question of self-plagiarism and miss-use of resources, or a typology and its punishment will be there today and as long as there is writing and research. The new trends in plagiarism and its rise is a challenge to all institutions of learning and there is need to teach plagiarism and good academic morals as a mission. Bibliography Blum, Susan D. My Word ! ,New York :Cornell University Press, 2009. Lathrop, Ann, and Kathleen Foss. Student Cheating and Plagiarism in the Internet Era: A Wake-Up Call: A Wake-Up Call. Englewood, Colorado: Libraries Unlimited, 2000. .eBook Collection (EBSCOhost), EBSCOhost (accessed March 9, 2017). Harris, Robert A. The Plagiarism, Handbook Los Angelas: Pyrczack publishing, 2001. Desena, Laura H. Preventing Plagiarism, Urbana: National Council of Teachers of English, 2007 [1] Blum, Susan D. My Word ! New York (Cornell University Press, 2009)12-13 [2] Acts 19: 14-16 (ESV) [3] Lathrop, Ann, and Kathleen Foss. Student Cheating and Plagiarism in the Internet Era: A Wake-Up Call: A Wake-Up Call. Englewood, Colorado: Libraries Unlimited, 2000. .eBook Collection (EBSCOhost), EBSCOhost (accessed March 9, 2017). [4] Harris, Robert A. The Plagiarism Handbook ( Los Angelas: Pyrczack publishing, 2001) ,23 [5] Desena, Laura H. Preventing Plagiarism (Urbana: National Council of Teachers of English, 2007 ),105.