1 Biology 321 Assignment Set #1 Spring 2013 Goals of this problems set: 1. To review basic Mendelian principles 2. To review meiosis and its connection to Mendel’s principles 3. To begin a consideration of probability and how it can be used to assess genetic data Required Reading Assignment Zebrafish researchers hook gene for human skin color Science 310: 1754 Dec. 16, 2005 http://fire.biol.wwu.edu/trent/trent/zebrafishskincolor.pdf Required Reading and Problem Assignments in Introduction to Genetic Analysis 10th edition. These are practice problems to prepare you for the quizzes and exams. I will not collect answers to these problems. Chapter 1 – Browse through this chapter. Look carefully at sections 1.1, 1.2, 1.3 (review of basics) & 1.5 (Model Organisms). Also browse through the Brief Guide to Model Organisms (starts on pg 759) and the Index to Model Organisms on the end papers at the back of the book Chapter 2 pgs. 27-42 & 49-50 (on testcrosses). Work problems 1, 2, 6, 15, 18, 23, 27, 30, 31, 36, 40, 50, 59 • NOTE on pg. 39: You are not responsible for yeast mating types. • Be sure to look carefully at Figure 2-11 illustrating the relationship between chromatids and DNA molecules Chapter 3 pgs. 81-89 (stop at Chi Square) & pgs. 94-100 Optional: read Section 3.5 on Organellar Genes Read through Solved problem 2. Work problems 12, 13, 18, 21, 25, 48 & 57 Using the 9th edition? It will work fine for most the course. Required Reading and Problem Assignments in 9th edition of text http://fire.biol.wwu.edu/trent/trent/assignmentset1.9.pdf2 Assignment Set 1 Problems sorted by analytical and/or content type Using and understanding genetic terminology Text Chapter 2: 2, This problem set: most of the questions Understanding Meiosis/mitosis & chromosome numbers Text Chapter 2: 18, 23, 27, 30, 31 Text Chapter 3: 13, 18, 21, 57 This problem set: 1a, 1b, 2, 3, 4, 13, 15, 17 Explaining/relating Mendel principles of inheritance with chromosome movement in meiosis Text Chapter 3: 21 This problem set: 17 Figuring out which trait is dominant: Text Chapter 2: 36, 40, 50 This problem set: 6, 8, 12 Assigning appropriate allele symbols Text Chapter 2: 40 This problem set: 8, 12, 14 Deducing parental and/or progeny genotypes from progeny phenotypic ratios data set large so ratios more or less match predicted probabilities for each phenotypic/genotypic class Text Chapter 2: 50 Text Chapter 3: Solved problem 2 (also 28 & 29– not officially assigned) This problem set: 8, 9, 10, 11 Using Mendel to predict progeny genotypes/phenotypes and ratios from parental genotypes/phenotypes Text Chapter 3: 12, 25, 48 This problem set: 7, 17 Sorting through the complexities of real data Text Chapter 2: 50 This problem set: 6, 7e, 12 Sorting through small data sets where progeny count will not necessarily match predicted probabilities for each phenotypic/genotypic class This problem set: 7e Basic Probability Product and Sum rules Text Chapter 2: 45 Text Chapter 3: 21, 25, 48 This problem set: 73 These are additionl practice problems to prepare you for the quizzes and exams. I will not collect the answers to these problems. ❖ Problem 1a 2n= 48 What does this symbolism tell you about the genetic content of a cell? Be explicit. 2: _______________ n: _______________ 48:______________ ❖ Problem 1b . The genetic content of a somatic tomato cell is 2n=24. How many different double-stranded DNA polymers comprise a single genome copy? ❖ Problem 2 Ferns have both a haploid and diploid stage in their life cycle. Early in the life cycle, all the cells in the prothallus (the young fern plant) are haploid. The prothallus is the gamete-producing stage of the life cycle. What type of nuclear division must be involved in the production of gametes by the prothallus? ❖ Problem 3 The common red fox has a genome content of 2n=38 chromosomes and the Arctic fox 2n=50. Viable, but sterile hybrid offspring can be produced from a mating between these two species. Studies of meiosis in these sterile hybrids have shown that both bivalents and univalents are present at metaphase I. a. How many chromosomes would the hybrid progeny have in each somatic cell? b. The production of viable but sterile offspring indicates that mitosis can proceed normally in these hybrid cells, but meiosis cannot. Briefly explain these observations in light of the differences between mitosis and meiosis. ❖ Problem 4 Many plants are polyploid, which means that they have more than two sets of chromosomes. Seedless strains of bananas and watermelon are triploid (3n) having 3 copies of each chromosome. Such triploids rarely produce viable seeds because the gametes produced during meiosis have “unbalanced” chromosome numbers (2 copies of some chromosomes and one copy of others). Briefly speculate on what problems a triploid cell might encounter when undergoing meiosis to produce these unbalanced gametes. ❖ Problem 5 Is it possible by breeding procedures alone to detect the presence of a gene if it exists in only one allelic form? Explain. ❖ Problem 6 You have recently purchased a red mare. You mate her to a black stallion and she produces twin foals: one red and one black. From this information, can you determine which trait is dominant? Explain your answer very briefly. What matings should you do to sort this out? Explain your answer and indicate the predicted results if red is dominant and if black is dominant. Be sure that your crosses will differentiate between the two possibilities. NOTE: there are a couple of possible strategies depending on what animals are available for mating.4 ❖ Problem 7 In Klingons, one gene determines hair texture while another determines whether the individual will have a saggital crest. K = curly klingon hair (dominant) k = silky earthling hair (recessive) S = large saggital crest (dominant) s = smooth, flat earthling forehead (recessive) Kayless is half human, half Klingon with a genotype of KkSs. He is mated to Lieutenant Worf’s sister, who is also heterozygous for both alleles. Dr. Beverly Crusher wants to better examine the genotypes of their offspring. Help her out by answering the following questions: a. What are the 4 possible phenotypes that may result from this mating? (Include a description of both hair and forehead for each phenotype.) b. What is the expected phenotypic ratio