Chapter 18 Genomes and Their Evolution

Name: Chapter 18 Active Reading Guide Genomes and Their Evolution Most AP Biology teachers think this chapter involves an advanced topic. The questions posed here will help you understand the general concepts over much of the chapter as well as a few more detailed questions in areas that are typical of biology courses at the freshman college level. Section 1 1. Craig Venter used an approach to genome sequencing termed the whole-genome shotgun approach. Explain how this concept can be used to sequence genomes. 2. What is a metagenome? How is metagenomics being used? Section 2 3. Bioinformatics is the application of statistics and computer science to the field of molecular biology. Describe four important examples of information that is available through bioinformatics. 4. What is the goal of scientists who study proteomics? 5. How might a human gene microarray chip be of medical importance? 1 Section 3 6. How do prokaryotic genomes of the two domains Bacteria and Archaea compare to eukaryotic genomes? 7. What relationship, if any, does a comparison of eukaryotic genomes indicate? Explain your response. 8. How are humans able to successfully compete in nature even though they have about the same number of genes as the nematode worm C. elegans? 9. What relationship does Chart 18.1 indicate for gene density comparisons between prokaryotes and eukaryotes? Section 4 10. Define the following two terms-pseudogene: repetitive DNA: 11. What are transposable elements, and what percentage of our genome is made of them? 12. Using Figure 18.5 in your text as a guide, list the types of DNA sequences in the human genome (greatest percentage first). 2 Chapter 18: Genomes and Their Evolution 139 d. sequences all the DNA in an environmental sample and uses computer software to assemble the se quences into specific genomes. applies genome-wide association studies to the iden-tification of human genes of medical importance. 3. Why is proteomics important in the systems bial-ogy approach? a. The interactions of networks of proteins are central to the functioning of cells and organisms. b. This bioinformatics field allows for the mathemat.cal modeling of biological systems. c. Determining the proteins expressed in a cell idern-tifies the genes more accurately than can be done through genomics. d. The three-dimensional structure of a protein can be used to predict its function. e. Comparing the proteins produced by a normal a lele and the allele associated with a disease can facilitate improved treatments. 4. Bacterial genes have an average length of 1.000 base pairs, human genes average about 27,000 base pairs. Which of the following statements is the best explanation for that difference? a. Prokaryotes have smaller, but many more, individ-ual genes. b. Prokaryotes are more ancient organisms, lenger genes arose later in evolution. c. Prokaryotes are unicellular, humans have many types of differentiated cells. d. Prokaryotic genes do not have introns, human genes have multiple introns. e. Prokaryotic proteins are not as large and complex as human proteins. 5. Which of the following statements best explains the discovery that a complex human has roughly the same number of genes as the simple nematode Celegans? a. The unusually long introns in human genes are in-volved in regulation of gene expression. b. More than one polypeptide can be produced from a human gene by alternative splicing. e. Human genes code for many more types of domains. d. The human genotne has a high proportion of nencod-ing DNA. The large number of SNPs (single nucleotide poly-morphisms) in the human genome provides a great deal of genetic variability. 6. Which of the following statements best describes what pseudogenes and introns have in common? a. They do not result in a functional product. b. They are DNA segments that lack a prometer but have other control regions. e. They are transcribed but their translation is blocked by miRNAs d. They code for RNA products, not proteins. e. They appear to have arisen from retrotransposons 7. Which of the following techniques can be used to determine the function of a newly identified gene? comparisons with genes of known functions that have similar sequences b. blockage of gene function to see the effect on the phenotype searches for similar sequences for domains of known function in other proteins. d. both a and b e. a, b, and e 8. Which of the following statements is not descrip tive of transposable elements? a. Barbara McClintock's work with maize provided the first evidence of such DNA segments. b. Transposable elements or related sequences make up 85% of the corn genome. c. Retrotransposons called LINE-1 are found within the introns of many human genes and may help regulate gene expression. d. Transposable elements often encode the enzymes, such as transposase or reverse transcriptase, reces sary for their movement. Each transposable element in present as multiple Identical copies, often clustered in the centromere or telomere regions of a chromosome. 9. The protein tissue plasminogen activator (TPA) has three types of domains. Which of the following statements best explains why one of each of these types of domains is found in three different pro-teins (epidermal growth factor, fibronectin, and plasminogen)? a. The genes for all four proteins are members of a mul tigene family involved in cell signaling. b. The gene for TPA was the first gene to evolve, the other three genes each lost two of the domains from the ancestral TFA gene. c. The gene for TPA arose by exon shuffling involvinį the other thuee genes. d. The gene for TPA has many Alir elements that pro vide alternative splice sites to incorporate thes exons e. Several duplication events led to the evolution of th TPA gene. 140 Unit 2: Genetics 10. Genes that are highly conserved are useful for identifying genes that led to new species. b. determining the function of newly discovered genes. c. establishing the sequence of divergence of closely re-lated species. d. tracing the relationships of groups that diverged early in the evolution of life. e. both a and e. 11. A highly conserved nucleotide sequence that has been found in developmental regulatory genes in many diverse organisins is called a. a homeodomain. b. a homeobox. c. a retrotransposon. d. a homeoxic gene. e. an Ll sequence 12. Which of the following approaches would be most useful in tracing human evolution? a. evo-devo and the comparison of developmental genes in plants and animals b. metagenomics and proteomics c. systems biology and the use of "knock-out" experiments d. analysis of single nucleotide polymorphisms and copy-number variants across individuals from the same and different populations e. All of the above make important contributions to studying the evolution of human populations. 13. What is the difference between a "copy and paste" transposon and a "cut and paste transposon? 14. Retrotransposons move by means of an RNA intermediate Explain how these common transposons accomplish this movement. 15. What is the role of reverse transcriptase? How might retroviruses be related to retrotransposons? 16. Transposons and retrotransposons comprise 20-50% of most mammalian genomes. What possible function might they have? 17. What are short tandem repeats (STRs), and why is the Innocence Project interested in them? 18. Describe and give an example of each of the following-multigene families of identical DNA sequences: multigene families of nonidentical genes: 19. How is fetal hemoglobin different from adult hemoglobin? What is the selective advantage of these different ẞ-globin genes? 3