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LJ Compton 2021 Eukaryotic and Bacterial Genetics Workshop Questions Instructions

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LJ Compton 2021 Eukaryotic and Bacterial Genetics Workshop Questions Instructions. Please work through all questions and make sure you understand the answers to all of them as these questions are very similar to those that you may be asked to answer in the May exam. For both Eukaryotic and Bacterial genetics sections, please submit your answers to Questions 1, 2 and 3 on the canvas quiz called Eukaryotic and Bacterial Genetic Analysis. Eukaryotic Genetics Q1-Q3 are worth 60 marks altogether. Bacterial Genetics Q1-Q3 are worth 40 marks altogether. Please prepare all of your answers offline before entering your answers into the quiz as you will only be able to submit your answers to the quiz once. For those quiz questions requiring a file upload, this can be a word doc or pdf with the answer either produced electronically or showing a hand draw diagram, either is fine as long as the content is laid out well and your working is easy to follow. Contents Eukaryotic Genetics Questions 1-3 to be submitted through canvas ......................... 1 Eukaryotic Genetics Questions continued – you do not need to submit these answers..................................................................................................................... 5 Bacterial Genetics Workshop Questions 1-3 to be submitted through canvas. .......... 7 Bacterial Genetics Questions continued – you do not need to submit these answers. ................................................................................................................................ 10 Eukaryotic Genetics Questions 1-3 to be submitted through canvas To answer these questions you will need to use a chi square probability table. 1. In a cross between two pure-breeding varieties of radish, one with red and the other with white roots, all the F1 progeny had purple roots. The F2 obtained by selfing the F1 segregated as follows: Red 80 Purple 222 White 98 Two models (A and B) were suggested to account for these results:A) Root colour is controlled by a single gene with two alleles (A1, A2) showing incomplete dominance. 1 LJ Compton 2021 B) Root colour is controlled by two unlinked genes showing (recessive) epistasis. With this hypothesis, the presence of pigment depends on a gene C while white roots are produced by its recessive allele, c. The second gene, R, controls the intensity of colour such that in the presence of C, the dominant allele R produces purple roots while the recessive allele, r, produces red roots. Which of these two hypotheses would you favour and why? To answer this, you will need to test the observed data against your predictions on both hypotheses by a chi-square test and work through the following sub-questions. For model A: 1a) Write out the genotypes of the two parents and the F1 individual (3 marks) 1b) Write out your null and alternative hypotheses for model A (3 marks) 1c) Draw a punnett square to show the expected genotypes in the F2 under model A (4 marks) 1d) What is your expected number of red individuals in the F2? (1 mark) 1e) What is your expected number of purple individuals in the F2? (1 mark) 1f) What is your chi square value for model A to 2 decimal places? (2 marks) 1g) How many degrees of freedom (df) does your chi square test have? (1 mark) 1h) Is model A a good fit to the data or not? (2 mark) For model B: 1i) Write out the genotypes of the two parents and the F1 individual (3 marks) 1j) Draw a punnett square to show the expected genotypes in the F2 under model B (4 marks) 1k) What is the expected ratio of purple:red:white phenotypes in the F2? (1 mark) 1l) What is your chi square value for model B to 2 decimal places? (2 marks) 1m) Based on the results of your chi squared test for models A and B, which of the two models would you favour? Briefly explain why. (3 marks) (Total 30 marks) Please submit your answers to this question via the canvas quiz sub questions 1-13 or 1a)-1m) which together are worth 30 marks. 2. Assume that the trait in the accompanying pedigree is due to simple Mendelian inheritance. Use A and a for the dominant and recessive alleles, respectively. 2 LJ Compton 2021 I II III IV a) Is the trait likely to be due to a dominant allele or a recessive allele? (1 mark) b) Briefly explain how you decided if the trait is dominant or recessive (2 marks) c) What is the biological relationship between individuals III-1 and III-2? (1 mark) d) If the allele responsible for the condition is rare, what are the most likely genotypes of the following individuals? (6 marks) Individual IV-4 Individuals IV-1, IV-2 and IV-3 Individual III-1 Individual III-2 Individual II-1 The parental individuals in generation I Please submit your answers to this question via the canvas quiz sub questions 1417 or 2a)-2d) which together are worth 10 marks. 3. An F1 plant (X) heterozygous for three genes (A/a, B/b, C/c) was test crossed to a plant homozygous for all three recessive alleles, a/a, b/b, c/c, with following results: Phenotype of progeny ABC abc ABc abC Abc aBC AbC aBc No. of plants Total 1000 4 3 414 413 26 27 58 55 3 LJ Compton 2021 a) Briefly explain how you can tell from the data that genes A, B and C are linked (2 marks) b) What were the genotypes of the two true breeding parents of individual X? Briefly explain your answer (5 marks) c) Calculate the recombination frequency between genes A and B and give your answer to 1 decimal place. (2 marks) d) Calculate the recombination frequency between genes A and C and give your answer to 1 decimal place. (2 marks) e) Calculate the recombination frequency between genes B and C and give your answer to 1 decimal place. (2 marks) f) Draw a map of the three genes indicating their map distances in cM (4 marks) (This map only needs to be approximately to scale). g) Add up the map distances in the two shortest intervals on your map. Does it equal the calculated map distance between the outer markers? Briefly explain your answer (3 marks) Please submit your answers to this question via the canvas quiz sub questions 1824 or 3a)-3g) which together are worth 20 marks. 4 LJ Compton 2021 8. A cross is made between a true-breeding shaggy Llama strain and a true-breeding short haired Llama strain. The shaggy Llamas are also homozygous brown: the shorthaired ones are homozygous cream coloured. An F2 from their progeny gave the following phenotypes Shaggy brown Short cream Shaggy cream Short brown 35 31 79 15 Propose a model to explain this pattern of phenotypes and test this model using a chi- square test. 9. Albinism in humans is inherited as a simple recessive trait. Determine the genotypes of the parents and offspring for the following families. When two alternative genotypes are possible, list both. Family A. Two non albino parents have five children, four normal and one albino. Family B. A normal male and an albino female have six children, all normal pigmentation. 6 LJ Compton 2021 Bacterial Genetics Workshop Questions. Useful formulae The distance between two markers for P1 transduction can be calculated using the formula: d=2* 1 3 f Where d is the distance (in minutes) between two genes Or d = 100 * 1 3 f Where d is the distance (in kb) between two genes and is the co-transduction frequency expressed as a fraction. Bacterial Genetics Workshop Questions 1-3 to be submitted through canvas. 1. argQ, cysY and fucA genes are genetically linked. The generalised transducing phage P1 was grown on a argQ+ cysY- fucA+ E. coli strain and used to infect a recipient strain with the genotype argQ- cysY+ fucA-. In experiment “A” 500 Arg+ transductants were screened for cotransduction of Cys- and Fuc+ and in experiment “B” 500 Fuc+ transductants were screened for cotransduction of Cysand Arg+. (Note: ArgQ and CysY are required for arginine and cysteine biosynthesis respectively and FucA is required for utilization of fucose as a carbon and energy source) (a) What growth medium was used for selection experiment A?(2 marks) (b) What growth medium was used for selection experiment B?(2 marks) Next, the transductants were screened for cotransduction of unselected phenotypes, with the following results. 7 LJ Compton 2021 Select Arg+ Screen: Select Fuc+ Screen: Arg+ 500 Arg+ 304 Cys- 30 Cys- 85 Fuc+ 305 Fuc+ 500 For the following questions please give your answers with two decimal places. (c) (d) (e) (f) (g) (h) (i) What is the co-transduction frequency for argQ and cysY? (2 marks) What is the co-transduction frequency for argQ and fucA? (2 marks) What is the co-transduction frequency for fucA and cysY? (2 marks) What is the distance in minutes between argQ and cysY? (2 marks) What is the distance in minutes between argQ and fucA? (2 marks) What is the distance in minutes between fucA and cysY? (2 marks) What is the order of the three genes along the chromosome? To answer this you may draw a map of the three genes showing the order and approximate distances between the three genes (1 mark) Please submit your answers to this question via the canvas quiz sub questions 2533 or 1a)-1i) which together are worth 17 marks. 2. This question requires you to think about the numbers of crossovers during homologous recombination required to achieve the stated outcomes. (a) How many recombination events are required for plasmid F to become an F’ carrying a single segment of the bacterial chromosome? (1 mark) Three genes are arranged in the order abcD, mnoP and xyzA. In a transformation experiment the DNA is made from a prototrophic strain and used to transform a triple mutant. (b) How many crossovers would be required to generate a stable strain that is phenotypically Abc+ Mno- Xyz+ (1 mark) (c) Illustrate your answer to 2b) using a simple diagram to show the crossovers involved (2 marks) In a second transformation experiment, the DNA is made from a triple mutant strain and used to transform a prototrophic strain. (d) How many crossovers would be required to generate a stable strain that is phenotypically Abc+ Mno- Xyz+ (1 mark) 8 LJ Compton 2021 (e) Illustrate your answer to 2d) using a simple diagram to show the crossovers involved (2 marks) Please submit your answers to this question via the canvas quiz sub questions 3438 or 2a)-2e) which together are worth 7 marks. 3. Five Hfr strains A through E are derived from a single F+ strain of E. coli. The following chart shows the entry times in minutes of the first five markers into an Fstrain when each Hfr strain is used in an interrupted-conjugation experiment: A mal+ strS ser+ ade+ his+ 1 11 16 36 51 B ade+ his+ gal+ pro+ met+ 13 28 38 44 70 C pro+ met+ xyl+ mal+ strS 3 29 32 37 47 D pro+ gal+ his+ ade+ ser+ 10 16 26 41 61 E his+ gal+ pro+ met+ xyl+ 7 17 23 49 52 a) Draw a map of the F+ strain, indicating the positions of all the genes and their distances apart in minutes (15 marks) Use arrowheads to show the insertion point and orientation of the F plasmid in each Hfr strain on your map. The arrowhead should point in the direction of gene transfer. b) When using Hfr strain A, which gene would select to obtain the highest frequency of donor alleles in the Hfr exconjugants (1 marks) Please submit your answers to this question via the canvas quiz sub questions 3940 or 3a)-3b) which together are worth 16 marks. 9 Chrome File Edit View History Bookmarks Profiles Tab Window Help A 2 Sun 9 May 07:48 slee x Digi x Quix Wee X L24 x Ord X Rec X C 1. In X C 1. In x C 9. A X C 4. A x NISO Mer x AB X prouse Mer x + k » ? canvas.bham.ac.uk/courses/46398/quizzes/104252/take ES M : LLL Apps Gmail YouTube Maps Reading List LIL CLA General Format || ... Secondary sources How to use the Ex... University Mental... MoveON - O Maximising the ou... recessive allele, c. The second gene, R, controls the Intensity of colour such that in the presence or C, the dominant allele R produces purple roots while the recessive allele, r, produces red roots. Which of these two hypotheses would you favour and why? To answer this, you will need to test the observed data against your predictions on both hypotheses by a chi-square test by working through the following steps. Account Dashboard Courses 33 Groups DOD DOD Question 1 3 pts Calendar ? Inbox Q1a) For model A) The genotypes of the two parents are and B History The genotype of the F1 individual is PebblePad Accessibility statement in 438 MAY 9 BO Métv 4 © W P X ))) Chrome File Edit View History Bookmarks Profiles Tab Window Help A 2 Sun 9 May 07:53 slee x Digi x Quix Wee x L24 x Ord X Rec X C 1. In X C 1. In x C 9. A X C 4. A x NISO Mer x AB X prouse Mer x + 6 k → C canvas.bham.ac.uk/courses/46398/quizzes/104252/take ES M : LLL Apps Gmail YouTube Maps CLA General Format 1.... Secondary sources How to use the Ex... University Mental... MoveON - O Maximising the ou... Reading List II Question 2 3 pts Q1b) Write out your null and alternative hypotheses for model A Account Dashboard Courses Edit View Insert Format Tools Table 33 Groups 12pt v Paragraph v Β Ι Ο A > Av Tv : DOD DOD Calendar ? Inbox B History PebblePad Accessibility statement p 20 words in 438 MAY 9 BO o “tv A ? W P X all Chrome File Edit View History Bookmarks Profiles Tab Window Help A 2 Sun 9 May 07:53 slee x Digi x Quix Wee X L24 x Ord X Rec X C 1. In X C 1. In x C 9. A X C 4. A x NISU Mer x AB X prouse Mer x + 6 k → C canvas.bham.ac.uk/courses/46398/quizzes/104252/take ES M : LLL Apps Gmail YouTube Maps CLA General Format || ... Secondary sources How to use the Ex... University Mental... MoveON - O Maximising the ou... Reading List II Q1c) Draw a punnett square to show the expected genotypes in the F2 under model A). Account Dashboard Courses Upload Choose a file 33 Groups DOD DOD Calendar ? Question 4 1 pts Inbox B History Q1d) For model A, what is your expected number of red individuals in the F2? PebblePad Accessibility statement {* lijs in BOKOBBERDEEHAU-ROOBoel.. 438 MAY 9 o “tv A ? W P X ))) Chrome File Edit View History Bookmarks Profiles Tab Window Help A se 2 Sun 9 May 07:55 slee x Digi x Quix Wee X L24 x Ord X Rec X C 1. In X C 1. In x C 9. A X C 4. A x NISO Mer x AB X prouse Mer x + 6 k → C canvas.bham.ac.uk/courses/46398/quizzes/104252/take ES M : LLL Apps Gmail YouTube Maps CLA General Format 1.... Secondary sources How to use the Ex... University Mental... MoveON - O Maximising the ou... Reading List LIL Question 8 2 pts Account to Q1h) Use your chi square value, degrees of freedom and the following probability table determine whether model A) is a good fit to the data. Dashboard and the model [ [ Select] > a good For model A [Select ] P0.05 Courses 33 Groups DOD DOD Calendar ? Inbox B History PebblePad Accessibility statement The following parts relate to Q1 model B. in 438 MAY 9 ! Métv & © W P X )))