Details of this Paper

Simulate basic principles of genetic inheritance based on Mendelian genetics

Description

solution


Question

The purpose of this laboratory is to do the following.;Simulate basic principles of genetic inheritance based on Mendelian genetics by designing and performing crosses between fruit flies.;Understand the relationship between an organism's genotype and its phenotype.;Getting to Know FlyLab: Performing Crosses;You will use FlyLab to study important introductory principles of genetics by designing and conducting mating between fruit flies with different characteristics that you have selected. These characteristics are the result of genetic mutations and may be recessive or dominant when compared to the wild type (WT) or normal phenotype. Can you define these terms? Before beginning each cross, consider what ratio of offspring you expect if the mutant trait is dominant. What if it is recessive? (Hint: Try a Punnett square for each mating!) Before beginning the lab, review the section in your text explaining Mendel's laws of segregation and independent assortment.;To begin an experiment, you must first design the phenotypes for the flies that will be mated. 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, antenna 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 that appears at the top of the FlyLab home page. When you select a particular phenotype, you are not provided with any information about the dominance or recessiveness of each mutation.;One advantage of FlyLab is that you will have the opportunity to study inheritance in large numbers of offspring. FlyLab will also introduce random experimental deviation to the data as it would occur in an actual experiment! As a result, the statistical analysis that you will apply to your data when performing chi-square analysis will provide you with a very accurate and realistic analysis of your data to confirm or refute your hypotheses.;To begin a cross, you must first select the phenotypes of the flies that you want to mate. Follow the directions below to create monohybrid and dihybrid crosses.;Deliverables;Your lab report should include the following.;This contains data from your first cross between a WT male and a WT female.;Answers in paragraph form to the questions listed in Parts A and B below;Part A;Data from your first cross between a WT male and a WT female;In this cross, we will review the process of sex determination. Before beginning, predict the ratio of male to female offspring you expect (remember that your data will not be perfect, round your ratio to the nearest whole numbers). When making your prediction, consider what determines male and female at the genetic level and how chromosomes are assorted in meiosis. Did your experimental ratio agree with your prediction? Explain how the distribution of X and Y chromosomes affects the ratio of males to females in the offspring.;Part B;Your data from the five monohybrid crosses;For each monohybrid cross, determine whether the mutants chosen are dominant or recessive to WT. You should be able to determine this from the phenotypic ratio of the F2 offspring. Before you begin, predict the ratio for a recessive mutation and dominant ratio, and then compare your data to your prediction. Be sure to click the ignore sex button when reviewing the data, in most cases, the sex of the fly is not relevant to the inheritance of the trait. Explain your choice. Which of Mendel's laws is demonstrated by a monohybrid cross?;This contains your data from the dihybrid cross.;What did you predict the phenotypic ration of the F2 offspring would be in this cross? Which of Mendel's laws is demonstrated here?;Grading Rubrics;Category Points Description;Part A;5;This contains data from your first cross between a WT male and a WT female.;Part A;5;In this cross, we will review the process of sex determination. Before beginning, predict the ratio of male to female offspring you expect (remember that your data will not be perfect, so round your ratio to the nearest whole numbers). When making your prediction, consider what determines male and female at the genetic level and how chromosomes are assorted in meiosis. Did your experimental ratio agree with your prediction? Explain how the distribution of X and Y chromosomes affects the ratio of males to females in the offspring.;Total;10;A quality lab report will meet or exceed all of the above requirements.;Category Points Description;Part B;5;Your data from the five monohybrid crosses;Part B;10;For each monohybrid cross, determine whether the mutant chosen is dominant or recessive to WT. You should be able to determine this from the phenotypic ratio of the F2 offspring. Before you begin, predict the ratio for a recessive mutation and dominant ratio, then compare your data to your prediction. Be sure to click the ignore sex button when reviewing the data, in most cases, the sex of the fly is not relevant to the inheritance of the trait. Explain your choice. Which of Mendel's laws is demonstrated by a monohybrid cross?;Part B;2;This contains your data from the dihybrid cross.;Part B;3;What did you predict the phenotypic ration of the F2 offspring would be in this cross? Which of Mendel's laws is demonstrated here?;Total;20;A quality lab report will meet or exceed all of the above requirements.;iLAB STEPS;Step 1: Introduction, Objectives, and Prerequisites;Back to Top;Once you get into the lab, read the introduction, objectives, and prerequisites. You will also need to read the background material to review important concepts behind the lab.;Getting Started;Welcome to FlyLab;This lab will show you how Mendel's Laws work in real life using fruit flies! It may take several minutes to load the application.;Step 2: Cross a WT Female With a WT Male Fly;Back to Top;To design a wild-type (WT) female fly, click the design button below the gray image of the female fly. Click the button for the eye color trait on the left side of the design view. The small button next to the words wild type should already be selected (bolded). To choose this phenotype, click the select button below the image of the fly at the bottom of the design screen. Remember that this fly represents a true-breeding parent that is homozygous for wild-type alleles. The selected female fly now appears on the screen with a + symbol indicating the wild-type phenotype. Do the same for the male fly.;Step 3: Mate the Two WT Flies;Back to Top;To select the number of offspring to create by this mating, click the pop-up menu on the left side of the screen and select 10,000 flies.;To mate the two flies, click the mate button between the two flies. Note the fly images that appear in the box at the bottom of the screen.;Scroll up to see the parent flies and down to see the wild-type offspring. These offspring are the F1 generation.;Click analyze results to see a table of your data. The data will be separated by male and female and by phenotype. In this cross, all the flies should have a WT phenotype indicated by a + sign.;The actual number of F1 offspring created by FlyLab does not exactly equal the 10,000 offspring that you selected. This difference represents the experimental error introduced by FlyLab.;Step 4: Save Your Results;Back to Top;To save the results of this cross to your lab notes, click the results summary button on the lower left side of the screen. A panel will appear with a summary of the results for this cross.;Note the number of offspring, proportion of each phenotype, and observed ratios for each observed phenotype.;Click the add to lab notes button at the bottom of the panel.;Click OK to close this panel. To comment on these results in your lab notes, click the lab notes button, move the cursor to the space above the dashed line, and type a comment such as, "These are the results of the F1 generation for my first monohybrid cross.;Click the close button to close this panel and return to the mate screen.;Step 5: Cross a WT Female With a Mutant Male;Back to Top;Take the cross to the F2 generation.;Design the female fly as described in Step 2 above.;Design a male fly with sepia eyes.;Click the design button below the gray image of the male fly.;Click the button for the eye color trait on the left side of the design view.;Click the small button next to the word Sepia. Note how eye color in this fly compares with the wild-type eye color.;Choose this fly by clicking on the select button below the image of the fly at the bottom of the design screen. The male fly now appears on the screen with the abbreviation SE indicating the sepia eye mutation. This fly is homozygous for the sepia eye allele. These two flies represent the parental generation (P generation) for your cross.;Based on what you know about the principles of Mendelian genetics (some traits are dominant and some are recessive or covered by the dominant traits), predict the phenotypic ratio that you would expect to see for the F1 offspring of this cross and describe the phenotype of each fly. Remember that the phenotype is what the organism looks like.;Mate the flies as described above. The data will be separated by both male and female and phenotype. In this case, we are only interested in the phenotype, the sex of the fly is irrelevant. To see only this data, click the ignore sex button in the data display. What did you expect if the mutant was recessive? Dominant? Which prediction do your data agree with?;To set up a cross between two F1 offspring, produce an F2 generation.;Be sure that you are looking at the two offspring flies in the box at the bottom of the screen. If not, scroll to the bottom of this box until the word offspring appears in the center of the box.;Click the select button below the female wild-type fly image, then click the select button below the male wild-type fly image. Note that the two F1 offspring that you just selected appear at the top of the screen as the flies chosen for your new mating.;Click the mate button between the two flies. The F2 generation of flies now appears in the box at the bottom of the screen. Use the scroll buttons to view the phenotypes of the F2 offspring (again be sure to ignore sex).;Examine the phenotypes of the offspring produced and save the results to your lab notes by clicking on the Results Summary button on the lower left side of the Mate view. Note the observed phenotypic ratios of the F2 offspring.;Click the add to lab notes button at the bottom of the panel. Click OK to close the panel.;Step 6: Repeat Steps 1?6 for Four Other Traits;Back to Top;Perform four more crosses as described above.;WT female X Vestigial wing (VG) male;WT female X Ebony body (E) male;WT female X Dumpy wing (Dp) male;WT female X Brown eye (BW) male;Before proceeding, do a Punnett square of each cross to predict the results if the mutation is recessive and if the mutation is dominant.;Based on what you know about the principles of Mendelian genetics (some traits are dominant and some are recessive), predict the phenotypic ratio that you would expect to see for the F1 and F2 offspring of this cross, and describe the phenotype of each fly. Remember that the phenotype is what the organism looks like.;Click the add to lab notes button at the bottom of the panel. Click OK to close the panel.;Step 7: Perform a Dihybrid Cross;Back to Top;In this cross, you will examine the inheritance of two phenotypes at the same time.;Design a WT female fly as above.;Design a male fly with both sepia eyes and dumpy wings (SE, Dp).;Mate these flies as above, carrying the cross to the F2 generation.;Based on what you know about the principles of Mendelian genetics, predict the phenotypic ratio you would expect to see for each generation.;Click the add to lab notes button at the bottom of the panel. Click OK to close the panel.;Step 8: Prepare Lab Report;Back to Top;Submit your answers to the following questions to the Dropbox in a Microsoft Word (.docx) file. Name your file Lab6_FIRSTNAME_LASTNAME.docx, using your name in the filename.;Saving Notebook Data: Exporting;In order to save the data you generate in Biology Labs Online, you will need to export it, that is, move it out of the lab or the notebook onto the computer desktop.;To save and export text, do the following.;Click on the export button in the Notebook.;After you click export, your notes are moved into the browser window. If you wish to save the document to a location other than the desktop, choose the drive or directory, then save the file.;Once you've saved the notes, you can copy and paste them to Microsoft Word as part of your lab report to be submitted to the Dropbox.;here is the link for the lab http://www.biologylabsonline.com/protected/FlyLab/flylab.php

 

Paper#15413 | Written in 18-Jul-2015

Price : $37
SiteLock