Hartwell Genetics Ch. 13 Study Guide

Chapter 13Chromosomal Rearrangements and Changes in Chromo somewhat Number Reshape eukaryote Genomes Fill in the Blank 1. Events that reshape genomes by reorganizing the desoxyribonucleic acid ranges in spite of appearance maven or to a greater extent chromosomes argon cognise as ____________________. autonomic nervous system rearrangements clog2 2. ____________________, geminations, upendings, translocations, and movements of ex departable particles be whole graphemes of rearrangements of chromosomal solid. autonomic nervous system Deletions hassle2 3. Very large deletions are visible at the relatively low resolution of a __________________, recording up as the loss of iodine or more bands from a chromosome. autonomic nervous system karyo example problem2 4. Changes in cistron ____________________, the lean of times a precondition divisor is present in the cell nucleus, cease create a constituenttic imbalance. autonomic nervous system dos pe riod bar3 5. An unpaired turn out of whizz member of a homologous pair of chromosomes during prophase of light reflex I is cognisen as a ____________________. autonomic nervous system deletion loop bar3 6. A recessive mutation in the mo wasting disease that prevents homozygous animals from walking in a straight line is known as the ____________________ gene. autonomic nervous system shaker-1 fuss3 7. When repeats of a region lie neighboring(a) to each separate they are called ____________________ extras. autonomic nervous system tandem hindrance2 8. Inversions that involve the centromere are termed ____________________. autonomic nervous system pericentric obstruction2 9. Inversions that toss out the centromere are termed ____________________. autonomic nervous system paracentric fuss2 10. A crossroad product that lacks a centromere is known as a(n) ____________________ ingredient. autonomic nervous system acentric hindrance2 11. The type of large-scale mutation in which split of ii dis analogous chromosomes trade pop outs is a ____________________ translocation. autonomic nervous system reciprocal problem2 12. ____________________ is the enzyme that catalyzes transposition. autonomic nervous system Transposase problem2 13. Organisms with four copies of a picky chromosome (2n+2) are ________________. autonomic nervous system tetrasomic fuss3 14. Down syndrome is also known as ____________________. autonomic nervous system trisomy 21 Difficulty2 15. If a tetraploid derives all of its chromosome commemorates from the same species, we call this kind of polyploid a(n) ____________________. Ans autopolyploid Difficulty3 Multiple Choice 16. Which of the pursuance are considered chromosomal rearrangements? A) anastrophes B) duplications C) deletions D) translocations E) all of the supra AnsE Difficulty1 17. Which of the following removes material from the genome? A) upen dings B) duplications C) deletions D) translocations E) none of the above AnsC Difficulty1 18. Which of the following adds material to the genome? A) sexual inversions B) duplications C) deletions D) translocations E) none of the above AnsB Difficulty1 19. The type of chromosomal rearrangement which commoves the desoxyribonucleic acid sequence at heart one chromosome is known as a(n) A) inversion B) duplication C) deletion D) translocation E) none of the above AnsA Difficulty2 20. In general, which of the following usually has a great chance of lethality than the others? A) inversion B) duplication C) deletion D) translocation E) all set about an satiscomponenty chance AnsC Difficulty2 21. Sometimes a piece of one chromosome attaches to a nonher chromosome.This is known as a(n) A) inversion B) duplication C) deletion D) translocation E) none of the above AnsD Difficulty1 22. Sometimes a disassemble of the genome m oves from chromosome to chromosome.This is known in the main as a(n) A) inversion B) duplication C) deletion D) translocation E) transposable element AnsE Difficulty2 23. Rearrangements and changes in chromosome come up whitethorn reckon gene operation or gene transmission by altering the ________________________ of certain genes in a cell. A) position B) order C) number D) all of the above AnsD Difficulty2 24. Karyotypes generally remain constant inwardly a species because A) rearrangements sink frequently. B) changes in chromosome number occur infrequently. C) genetic instabilities produced by genomic changes usually are at a selective disadvantage. D) genetic imbalances are often at a selective advantage. AnsC Difficulty2 25. Despite selection against chromosomal variations A) related species almost evermore engender the same karyotype. B) related species almost always deem a diverse karyotype. C) well-nigh related species dive rge by many chromosomal rearrangements. D) distantly related species diverge by only a few chromosomal rearrangements. AnsB Difficulty2 26. In higher(prenominal) organisms, using genetic abbreviation is usually difficult to distinguish subatomic deletions in one gene from A) heterozygotes. B) small duplications. C) monosomies. D) run mutations. AnsD Difficulty1 27. For an organism to survive a deletion of more than a few genes, it must carry a nondeleted homolog of the deleted chromosome. This is known as A) a deletion heterozygote. B) a deletion homozygote. C) dosage compensation. D) a triplolethal chromosome. AnsA Difficulty2 28. Individuals born heterozygotes for certain deletions check a greatly increased risk of losing both copies of certain genes and developing cancer. one(a) such disease is A) triplolethal. B) scarlet eyes. C) retinoblastoma. D) catar arranges. AnsC Difficulty1 29. During the pairing of homologs in prophase of meio sis I, the region of a normal, nondeleted chromosome that has nonhing with which to change forms a so-called A) inversion loop. B) deletion heterozygote. C) crossover suppressor. D) deletion loop. AnsD Difficulty2 30. Using Drosophila polytene chromosomes and small deletions, geneticists shed been able to A) routine the shaker-1 gene in Drosophila. B) assign genes to regions of one or devil polytene chromosome bands. C) assign genes to regions of 100kb or less of desoxyribonucleic acid. D) all of the above AnsD Difficulty2 31. Which of the following molecular techniques could a scientist use to help locate genes on cloned fragments of DNA with deletion mutants? A) In situ hybrid B) Crossover analysis C) Southern blot analysis D) all of the above E) both a and c AnsE Difficulty3 32. Duplications rally by A) chromosomal breakage and faulty repair. B) unequal pass over. C) errors in replication. D) all of the above AnsD Difficulty1 3 3. During the pairing of homologs in prophase of meiosis I, the region of a chromosome bearing tautological copies of a particular chromosomal region that has nothing with which to recombine forms a so-called A) inversion loop. B) deletion heterozygote. C) duplication loop. D) deletion loop. AnsC Difficulty2 34. An inversion whitethorn result from A) a half-circle whirling of a chromosomal region following 2 double-strand breaks in a chromosomes DNA. B) the action of a transposable element. C) a crossover between DNA sequences present in two positions on the same chromosome in alter orientation. D) all of the above E) none of the above AnsD Difficulty2 35. Inversions may be hard to detect because they A) never visibly change chromosome banding patterns. B) increase recombination in heterozygotes. C) do not usually cause an abnormal phenotype. D) normally are removed immediately in natural populations. AnsC Difficulty3 36. Which of the following does not happen when an intragenic inversion occurs? A) One part of the gene is relocated to a distant region of the chromosome. B) One part of the gene stays at its first site. C) Homozygotes for the inversion do not survive. D) The genes function is not disrupted. AnsD Difficulty3 37. When a crossover occurs at bottom the inversion loop of a pericentric inversion each recombinant chromatid give up for have A) a single centromere. B) a duplication of one region. C) a deletion different from the one of duplication. D) all of the above AnsD Difficulty2 38. Robertsonian translocations result from which of the following? A) Breaks at or near the centromeres of two acrocentric chromosomes followed by the reciprocal exchange of broken parts. B) A part of one chromosome be get alongs attached to a non-homologous chromosome. C) Unequal crossing over during meiosis. D) The coalition of two small chromosomes end-to-end such that a double centromere occurs. AnsA Difficulty2 39. Which of the following does not usually show a problem during meiosis? A) translocation heterozygotes B) translocation homozygotes C) paracentric inversion D) pericentric inversion AnsB Difficulty1 40. Of the following segregation patterns, which one is most potential to result in a normal zygote? A) alternate B) neighboring(a)-1 C) adjacent-2 D) nondisjunction AnsA Difficulty2 41. The condition of semisterility is most closely associated with A) chromosomal duplications. B) pericentric inversions. C) translocation heterozygotes. D) translocation homozygotes. AnsC Difficulty2 42. Translocations can help A) work linkage groups. B) aid in the diagnosis and treatment of certain cancers. C) map important genes. D) all of the above AnsD Difficulty1 43. Down Syndrome can result from A) three copies of chromosome 21. B) a translocation of a part of chromosome 21. C) a reciprocal translocation between any two autosomes. D) a a nd b E) a, b, and c AnsD Difficulty2 44. Which of the following do translocations and inversions not have in common? A) dont alter the amount of DNA in the genome B) ability to alter gene function C) use of inversion loops during crossing over D) catalysts of speciation AnsC Difficulty2 45. A transposition is considered a cytologically invisible sequence rearrangement. With which of the following does it share this blank space? A) small deletion B) large duplication C) inversion D) translocation AnsA Difficulty2 46. Barbara McClintock is most closely associated with which of the following? A) The initial denudation of genetic transposition. B) The disco real of transposable elements in corn. C) The mutation rate in translocation heterozygotes. D) The demonstration of the presence of transposable elements in polytene chromosomes. AnsB Difficulty1 47. Transposable elements have many things in common.Which of the following is not a usual charac teristic of them? A) Typically smaller than 50 bp. B) whitethorn be present in a genome from one to thousands of times. C) Are found only in a select group of organisms. D) Need not be sequences that do something for the organism. AnsA Difficulty3 48. Retroposons and retro-viruses have structural parallels. Which of the following also shares structural parallels with them? A) tRNA B) DS-DNA C) rRNA D) mRNA AnsD Difficulty2 49. Which of the following is a possible install that a transposable element may have on a gene? A) Shift the reading frame. B) Diminish the efficiency of splicing. C) Provide a transcription stop signal. D) all of the above AnsD Difficulty2 50. Which of the following is not an aneuploidy? A) monosomy B) tetraploid C) trisomy D) tetrasomy AnsB Difficulty1 51. The most common forgiving aneuploidy is trisomy 21, Down syndrome.All of the launchs listed below may be seen in this syndrome except A) death always by age 2 5. B) mental retardation. C) careworn abnormalities. D) heart defects. E) increased susceptibility to infection. AnsA Difficulty2 52. Which of the following sex chromosome aneuploidies is not usually seen in live births? A) XO B) XXY C) YO D) XXX E) None of the above AnsC Difficulty2 53. Turner syndrome, XO, is a sex chromosome aneuploidy. Of the effects listed below, which one is not usually seen in this syndrome? A) unusually short stature B) infertility C) skeletal abnormalities D) unusually long limbs AnsD Difficulty2 54. In Drosophila, a gynandromorph, which is composed of equal parts male and female tissue, results from A) an XX female losing one X chromosome during the first mitotic division after fertilization. B) an eggs carrying an X chromosome fertilized by a Y-carrying sperm. C) a normal egg fertilized by both an X-carrying sperm and a Y-carrying sperm. D) the fusion of a female embryo with a male embryo. AnsA Difficulty3 55. W hich of the following is not an example of a euploid condition? A) triploidy B) diploidy C) Down syndrome D) tetraploidy AnsC Difficulty1 56. Triploid organisms usually result from A) the union of haploidic and diploid gametes. B) unequal disjunction during embryogenesis. C) propagation of fused cell lines. D) fusion of three gametes simultaneously. AnsA Difficulty2 57. During mitosis, if the chromosomes in a diploid tissue fail to separate after replication, the resulting daughter cells bequeath be A) haploid. B) tetrasomic. C) triploid. D) tetraploid. AnsD Difficulty2 58. Hybrids in which the chromosome sets come from two distinct, though related, species are known as A) autopolyploids. B) allopolyploids. C) amphiploids. D) bivalents. AnsB Difficulty2 59. The genus Triticale is a tonicly genus of the various allopolyploid hybrids between wheat and rye whisky whisky.Some of the members of this genus show agricultural promise because A) wheat has a high yield. B) rye adapts well to unfavorable environments. C) wheat has a high level of protein. D) rye has a high level of lysine. E) all of the above AnsE Difficulty2 60. Which of the following rarely, if ever, results in a positive wad for evolution? A) polyploidy B) allopolyploidy C) trisomy D) amphidiploidy AnsC Difficulty2 pairing Match the following descriptions with the terms below a. inversion b. duplication c. deletion d. translocation e. transposable element 61. A piece of genetic material that moves from place to place in the genome. Ans e Difficulty2 62. A change in the genome whereby new material is added to the genome. Ans b Difficulty1 63. A change in the genetic material where a DNA sequence changes direction. Ans a Difficulty1 64. A hang of genetic material in the genome. Ans c Difficulty1 65. A piece of chromosome attaches to another chromosome. Ans d Difficulty2 Match the following descriptions wit h the terms below a. retroposon b. transposon c. transposable element d. transposase 66. Any DNA segment that moves about in the genome. Ans c Difficulty3 67. Moves in the genome with the aid of an RNA intermediate. Ans a Difficulty2 68. Moves DNA directly. Ans b Difficulty3 69. An enzyme that catalyzes a transposition event. Ans d Difficulty1 unbent or False 70. When comparing pilfer and human Giemsa-stained karyotypes, we see no conservation of banding patterns. Ans real Difficulty2 71. Karyotypes generally remain constant within a species because rearrangements and changes in chromosome number occur infrequently. AnsFalse Difficulty3 72. Changes in chromosome number include aneuploidy, monoploidy, polyploidy, and duplications. AnsFalse Difficulty2 73. Deletion may arise from errors in replication, from faulty meiotic or mitotic recombination, and from exposure to X-rays. AnsTrue Difficulty2 74. Homozygosity for a deletion is often, but not always, lethal. AnsTrue Difficulty2 75. Recessive mutations can often be covered by deletions in heterozygotes. AnsTrue Difficulty2 76. Most duplications have no obvious phenotypic consequences and can be detected only by cytological or molecular means. AnsFalse Difficulty2 77. Duplication of chromosomal segments rarely has an effect on the evolution of genomes. AnsTrue Difficulty2 78. Crossing-over within an inversion loop produces aberrant recombinant chromatids. AnsFalse Difficulty3 79. Reciprocal translocations are usually phenotypically abnormal because they have n either lose nor gained genetic material. AnsTrue Difficulty1 80. A trademark of transposons is that their ends are inverted repeats of each other. AnsFalse Difficulty3 81. The pinch genome has high synteny with the human genome since about 170 DNA blocks are evidently rearranged between the two genomes. AnsTrue Difficulty2 82. Euploid cells contain on ly incomplete sets of chromosomes. AnsFalse Difficulty2 83. Down syndrome is an example of triploidy. AnsFalse Difficulty2 84. contagious imbalance results from polyploidy. AnsFalse Difficulty1 85. An acentric fragment is an inversion cross-over product lacking a centromere. AnsTrue Difficulty1 Short Answer 86. develop how data from the linkage groups of the mouse can be used as a resource for assessing human linkage groups. Ans Because virtually all genes cloned from the mouse genome are conserve in the human genome and vice versa, it is possible to construct linkage maps for the two genomes from the same set of markers. Comparisons of the mouse and human linkage groups allow one to see a picture somewhere between complete equipoise and unrelatedness. Genes closely joined in the mouse tend to be closely linked in humans, but genes that are less tightly linked in one species tend not to be linked at all in the other. This shows that even though mi ce and humans diverged about 65 million years ago, the DNA sequences in many regions are very similar. Difficulty4 87. Explain the contrasts between chromosomal rearrangements and changes in chromosome number. diagnose at least one example of each. Ans Chromosomal rearrangements reorganize the DNA sequences within one or more chromosomes. Changes in chromosome number involve losses or gains of entire chromosomes or sets of chromosomes. (Student may honorable call forth as an example of rearrangements deletion, duplication, inversion, translocation, and transposable elements. For changes in chromosome number student may cite an aneuploidy such as a monosomy or trisomy, monoploidy, or polyploidy. Difficulty4 88. Describe how an inversion heterozygote can reduce the number of recombinant publication. Ans When inversion heterozygotes have chromosomes pair up during meiosis, an inversion loop is organize to allow the tightest possible alignment of homologous region s. This always produces aberrant recombinant chromatids. twain inversion cases are possible pericentric and paracentric. In a pericentric crossover within the inversion loop each recombinant depart carry a duplication of one region and a deletion of another.This abnormal dosage of some genes bequeath result in abnormal gametes and if they fertilize normal gametes, zygotes may die because of genetic imbalance. In a paracentric crossover within the inversion loop the recombinant chromatids will be sick in both gene dosage and centromere number. (Student may then relieve how centromere number can result in genetically unbalanced gametes such as what acentric and dicentric chromatids would produce. ) Difficulty4 89. Discuss the several effects that translocations and inversions have in common. Ans Both translocations and inversions change genomic position without affecting the chalk up amount of DNA. If a breakpoint of either one is within a gene, the gene functi on may be altered or lost. Both types may produce genetically imbalanced gametes that may negatively affect a zygote or developing embryo. (Student may explain at this point the differences between how the imbalanced gametes are produced. ) Because both reduce viable progeny and heterozygotes, they may play a role in speciation and evolution. Difficulty4 90. Explain the possible effects that a transposable element may have on a gene. Ans Insertion of a transposable element near or within a gene can affect gene brass and alter phenotype. For example, a B type hemophilia occurs after entry of Alu into the gene en mark clotting factor IX. Secondly, the effect of insertion depends on what the element is and where the insertion point is. If insertion is into a protein-coding exon, the reading frame may shift or a stop codon may be introduced. Insertion into an intron may tear down the efficiency of splicing, which may result in removal from the transcript that could c ast down production of a normal polypeptide.A stop signal could also affect genes downstream. Upstream insertion into a regulatory gene could affect gene function in various ways also. Difficulty4 91. Explain the mechanism by which aneuploidy occurs. Ans Aneuploidy occurs because of meiotic nondisjunction either in meiosis I or meiosis II. In meiosis I if homologs do not separate all gametes produced will contain an error. Two of the gametes will contain both homologs and two will contain neither.When fertilization of a normal gamete occurs by either of these abnormal gametes, aneuploidy results. Half of the zygotes will be trisomic and half will be monosomic. Meiotic nondisjunction during meiosis II will produce two normal and two abnormal gametes. If fertilization occurs with either of the abnormal gametes, aneuploid zygotes are produced. Difficulty4 92. Discuss why triploid organisms are almost always sterile. Ans (Student may explain how triploids occur. ) Triploids are almost always sterile because meiosis produces mostly unbalanced gametes.During the first meiotic division in a triploid microbe cell, three sets of chromosomes must segregate into two daughter cells. Most in all likelihood one daughter will end up with two chromosomes and the other will have only one of any one set of homologs. Some cells will have two of some chromosomes and the normal one of others. Many combinations of incorrect number of chromosomes will occur with very brusk chance of the normal amount. Most gametes will be aberrant and will have a reduced chance of producing viable offspring. Difficulty4 93. Discuss how deletions and duplications may contribute to evolution. Ans General examples of how chromosomal rearrangements power contribute to evolution Deletions a small deletion that moves a coding sequence of one gene next to a promoter or other regulatory element of an adjacent gene may, rarely, allow expression of a protein at a novel time in maturement or in a novel tissue. If the new time or place of expression is advantageous to the organism, it might become established in the genome. Duplications a duplication will provide at least two copies of a gene. If one copy maintains the original function, the other could conceivably ingest a new function that would probably be related to the original function.Many examples can be seen in higher plants and animals. (Students may also publish about the evolutionary contributions of the other chromosomal rearrangements and might even mention the role of changes in chromosome number. ) Difficulty4 94. Why do inversions act as cross-over suppressors? Ans Inversions act as cross-over suppressors because only progeny that do not recombine within an inversion loop will survive. Difficulty4 95. What is a balancer chromosome? Ans A balancer chromosome is a special chromosome often created by the use of X-rays for the purpose of genetic usage these chrom osomes often carry multiple, overlapping inversions that enable researchers to follow them through crosses, and a recessive lethal mutation that prevents the survival of homozygotes. Difficulty4 96. What is the difference between alternate and an adjacent-1 segregation or an adjacent-2 segregation pattern? Ans An alternate segregation pattern results in balanced chromosomes while adjacent 1or 2 patterns yield chromosomes that are unbalanced. Difficulty4 Experimental determination and Interpretation of Data 97. We now know that several organisms have a high degree of synteny at the genomic level. You wish to test the hypothesis that the research lab mouse and human share genomic similarities. What tests would you complete and given that we now know that the mouse and human genomes are highly syntenic, what results would you expect? Ans Karyotype analysis can be used to test the hypothesis of genomic similarities however, only animals that have high homology will sh ow similar banding patterns.Therefore, look for (fluorescence in situ hybridization) would be a more useful technique to determine synteny. The mouse and human genomes are similar in that approximately 170 similar fragments an average length of about 18 Mb are simply rearranged (this is not visible in a karyotype). Difficulty4 98. You are mapping traits in your favorite organism but unbeknownst to you, your laboratory model organism contains a rare deletion. How will your mapping results be affected? Ans The mapping distance will appear smaller than the actual physical distance in the wild-type organism. Difficulty4 99. You have discovered an altered phenotype and cloned the gene responsible. However, the gene you cloned appears to have an unusual sequence in it. In order to determine the chromosomal location of your new gene, you perform FISH, using only the unusual sequence, on several animals. To your surprise, the FISH results suggest that each animal contains the gene on a different chromosome. How would you interpret your results. Ans The unusual sequence is a transposon and your new phenotype arose via the disruption of its gene by the transposon. Difficulty4 100. You are a master gardener and your favorite tomato plant is very reasonable to a pesticide called DEADBUG. You wish to make your special tomato plants resistant to the pesticide which you spraying on other bushes in your garden. Using microbial techniques give satisfactory and complete details of how you would do this (include ploidy status). Ans Haploid pollen grains are stone-cold set and plated on agar plates.The resulting embryoids are treated with hormone in liquid culture and eventually grown as a monoploid plant. The plant is treated with a mutagen to induce mutations that can result in insensitivity to the pesticide. Somatic cells are removed from the treated plant and plated on agar containing DEADBUG. Only cells resistant to DEADBUG will grow. A gain the embryoid is hormone treated and grown into a resistant monoploid plant. Treatment with colchicine will allow duplication of chromosomes without separation resulting in a normal diploid plant. Difficulty4