1999 - THE UNIVERSITY OF HONG KONG BACHELOR OF SCIENCE...

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Unformatted text preview: THE UNIVERSITY OF HONG KONG BACHELOR OF SCIENCE: FIRST EXAMINATION BOTANY/ZOOLOGY: BIOL1106 Genetics 18 May1999 9.30 am—11.30am Candidates may use any self-contained, silent, battery-operated and pocket-sized calculator. The calculator should have numeral-display facilities only and should be used only for the purpose of calculation. It is the candidate’s responsibility to ensure that his/her calculator operates satisfactorily. Candidates must record the name and type of their calculators on the front page of their examination scripts. Answer any FIVE questions. All questions carry equal marks. 1. In tomato plants, hairy stems are produced by a dominant allele, H, and nonhairy stems arise from the expression of its recessive counterpart allele, h. For the trait of plant height, a dominant allele, D, produces tall plants while expression of the recessive allele, d, produces dwarf plants. The two loci are located on different chromosomes. You are given a tomato plant which has a hairy stem and is tall. Nothing is known about the specific genotype of this plant. (a) Identify all possible genotypes for this plant. (b) What procedure could be used to identify the genotype of this particular plant? (c) Assume that the plant in question is crossed with a plant with nonhairy stems and dwarf height. Two phenotypes are found in roughly equal numbers among the 316 progeny plants. Based on this information, what can be concluded about the genetic makeup of the hairy, tall parental plant? Of the 316 progeny plants, roughly half were hairy, tall and the rest were hairy, dwarf. With this additional information, what can be said about the genotype of the hairy, tall parental plant? (d) 2. Write briefly on each of the following terms. (a) genetic variation (b) meiosis and mitosis (c) telomere (d) centromere 3. Describe the important features of the DNA molecule and discuss how DNA can serve as a genetic material. 4. Discuss the significance of the chromosome number. 5. The MN blood types are due to two alleles M and N at a single locus. In a sample of 1000 people, there were 300W 485 MN, and 215 NN genotypes. a) What are the allele frequencies of M and N? b) What is the frequency of heterozygotes? c) What is the frequency of homozygotes? . d) Determine whether these genotype frequencies are in accord with Hardy-Weinberg frequencies. (A Chi-Square table is attached below). The probabilities of cxeeodhg dlfioronf chi-square vuluos for degree; of frecdcm from 1 to 50 when the expected hypochosis 1: true' Prob-hm?!” 41‘ .95 .90 .70 .50 .30 .20 .10 .05 .01 .00] 1 .004 .016 .15 .46 1.07 1.64 2.71 3.84 6.64 10.83 2 .10 .21 .71 1.39 2.41 3.22 4.61 5.99 9.21 13.82 J .35 - .58 1.42 2.37 3.67 4.64 6.25 7.82 1 1.35 16.27 4 .71 1.06 7.20 3.36 4.88 5.99 7.78 9.49 13.28 18.47 5 1.15' 1.61 3.00 4.35 6.06 7.29 9.24 11.07 15.09 20.52 6 1.64 2.20 3.83 5.35 7.23 8.56 10.65 12.59 16.81 2246 7 2.17 2.83 4.67 6.35 8.38 9.80 12.02 14.07 18.48 24.32 8 2.73 3.49 5.53 7.34 9.52 11.03 13.36 15.51 20.09 26.13 9 3.33 4.17 6.39 8.34 10.66 12.24 14.68 16.92 21.67 27.88 I 0 3.94 4.87 7.27 9.34 11.78 13.44 15.99 18.31 23.21 29.59 H 4.58 5.58 8.15 10.34 12.90 14.63 17.28 19.68 24.73 31.26 [2 5.23 6.30 9.03 11.34 14.01 15.81 18.55 ' 21.03 26.22 32.91 13 5.89 7.04 9.93 12.34 15.12 16.99 19.81 22.36 27.69 34.53 [4 6.57 7.79 10.82 13.34 16.22 18.15 21.06 23.69 29.14 36.12 15 7.26 8.55 1 1.72 14.34 17.32 19.31 22.31 25.00 30.58 37.70 20 10.85 12.44 16.27 19.34 22.78 25.04 28.41 31.41 37.57 45.32 25 14.61 16.47 20.87 24.34 28. I 7 30.68 34.38 37.65 44.31 52.62 30 18.49 20.60 25.51 29.34 33.53 36.25 40.26 43.77 50.89 59.70 50 34.76 37.69 44.31 49.34 54.72 58.16 63.17 67.51 76.15 86.66 at .05 level ‘ W [run Table IV of Fisher and Yd”. Shiitficol Tabb: for liohgiaal, Agriculde and Mar-cal Ronald]. Oliver and ond ud., Edinburgh, by puniuion 6‘ 11» when and purl-thou. 6. It has been hypothesized that the mitochondrion arose Via symbiosis, i.e., an ancient bacterium came to live inside an eukaryotic organism and gradually evolved to become today’s mitochondria in most eukaryotes. From which gene does the genetic evidence for this hypothesis come from? Why is this gene a good choice for the study? In order to find out whether female P. leucopus in natural populations have mated with multiple males, pregnant females were caught and allowed to give birth in the laboratory. Electrophoresis was done and genotypes of 10 females and their offspring are listed below. Write down the ID number for those females that have definitely mated with more than one male. Can we say that the rest of females have mated with just a single male? If not, why not? _____Mch.er__________Qfisnring____—__ I BB BB BB BC BC BC BC II BB BB BB BC BB BC BC III BB AB AB AB BB BB AB IV BB AB AB BB BB AB BB V AB AB AB AB AB BB BB VI BB AB AB BB BB BB BB VII BB AB AB BB BB AB AB VIII AB AB AD AD AD BC BC IX BB AB AB BB BB BB BC X__BB_____.BIL__EB__BB____BB___BB__BR_ END OF PAPER ...
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This note was uploaded on 03/18/2010 for the course BOTANY/ZOO BIOL1106 taught by Professor Drp.c.leung during the Spring '99 term at HKU.

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1999 - THE UNIVERSITY OF HONG KONG BACHELOR OF SCIENCE...

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