Chapter 11 dna biology & technology

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Chapter 11 dna biology & technology

  1. 1. Introduction to Biology Chapter 11Professor Zaki Sherif, MD., PhD Strayer University
  2. 2. Essentials of Biology Sylvia S. Mader Chapter 11 Lecture OutlineCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  3. 3. 11.1 DNA and RNA Structure and Function• Mendel knew nothing about DNA.• It took years for investigators to conclude Mendel’s factors (genes) were on chromosomes.• There was a controversy over whether DNA or protein was the genetic message. • Experiment using viruses showed only DNA directed the formation of new viruses.
  4. 4. Figure 11.1 The genes are composed of DNA.•Alfred Hershey and Martha Chase determined that DNAis the genetic material.•Their experiment involved a virus which infects bacteriasuch as E. coli.•They wanted to know which part of the virus entered thebacterium: •Capsid made of protein •DNA inside the capsid•Radioactive tracers showed that DNA, not protein,enters the bacterium and guides the formation of newviruses.•Therefore, DNA must be the genetic material.
  5. 5. Figure 11.1 The genes are composed of DNA Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. DNA capsid E. coli cytoplasm (tissue left): © Sercomi/Photo Researchers, Inc.
  6. 6. • Structure of DNA  Race to determine the structure  Chargaff’s Rules • Knew DNA contains 4 types of nucleotides • Examined DNA from many species 1.The amount of A, T, G, and C in DNA varies from species to species. 2.In each species, the amount of A = T and the amount of G = C.  All nucleotides contain phosphate, a 5-carbon sugar, and a nitrogen-containing base.
  7. 7. Figure 11.2 Nucleotide composition of DNA and RNA Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. C P CH2 O sugar OH a.
  8. 8. Figure 11.2 continued Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nitrogen-containing bases NH2 O Phosphate C C N H N O N C N C C H C H HO P O– H C C C C N N H2N N N – O H H Adenine (A) Guanine (G) b. Sugars H H NH2 O O HO C H HO C H C H C CH3 C H O OH O OH N C H N C H N C C H H C C H H C C C H C C C C O N O N H O N H H C C H H C C H H H H OH H OH OH Cytosine (C) Thymine (T) Uracil (U) deoxyribose ribose (DNA only) (RNA only) (DNA only) (RNA only)c. d.
  9. 9. Figure 11.3 X-raydiffraction pattern • Franklin’s X-ray diffractionof DNA data  Rosalind Franklin was studying the structure of DNA.  Her data showed DNA to be a helix with some portions repeating over and over.
  10. 10. Figure 11.4 Watson and Crick• The Watson and Crick model of DNA Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Model  James Watson and Francis Crick set out to bring together all the data on DNA and build a model.  The model suggested how replication works.  Their model holds true today with few changes.  Won the Nobel Prize © A. Barrington Brown/Photo Researchers, Inc. James Watson (left) and Francis Crick (right)
  11. 11. • DNA structure  DNA structure is a double helix, like a twisted ladder.  Deoxyribose sugar and phosphate molecules are bonded, forming the sides, with the bases making up the rungs of the ladder.  Complementary base pairing of A&T and G&C  Hydrogen bonding between the bases holds halves of helix together.
  12. 12. Figure 11.5 DNA structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. C P sugar-phosphate G C backbone P G T A P P A a. Space-filling model T P complementary base pairing P hydrogen bond OH G P 2′ 3′ 5′ T C 1′ A 1′ S 4′ 4′ S P 3′ 2′ 5′ 3′ end 5′ end P C P OH b. Nucleotide pair 5′ end G P hydrogen bonds sugar OH 3′ end c. Structure of DNA © Photodisk Red/Getty RF
  13. 13. • Replication of DNA  Process of copying DNA before cell division  2 strands separate • Each strand serves as a template for a new strand  Semiconservative – each new DNA molecule is made of one parent strand and one new strand.  Replication requires • Unwinding – helicase • Complementary base pairing • Joining – DNA polymerase and DNA ligase  New DNA molecule exactly identical to original molecule.
  14. 14. • Semiconservative Replication  Parent strand unwinds and separates by actions of helicase.  New strands form through complementary base pairing by actions of DNA polymerase.  DNA ligase seals any breaks in the sugar-phosphate backbone.  New DNA molecule will be half old and half new.  New DNA molecule will be exactly identical to original molecule.
  15. 15. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 11.6 3′ 5′ Semiconservative replication G G C parental DNA helix G G C G C movement C of G C C region of replication: New replication G nucleotides are pairing with for K A those of parental strands. A G T T G G T A C region of completed G replication C G G G G direction C of DNA C sythesis 3′ G 5′ C G new old strand strand C G daughter molecule 5′ 3′ old new strand strand daughter molecule
  16. 16. • In eukaryotes, DNA replication begins at numerous origins of replication.  Forms “replication bubbles”  Bubbles spread in both directions until they meet.
  17. 17. Figure 11.7 Eukaryotic replication Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. replication bubble fork daughter daughter strand DNA molecules parental strand
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  19. 19. • RNA structure and function  Ribonucleic acid (RNA)  Contains sugar ribose  Uses uracil, not thymine • Uses A, C, and G like DNA  Single-stranded  3 majors types • Messenger RNA (mRNA) • Transfer RNA (tRNA) • Ribosomal RNA (rRNA)
  20. 20. Figure 11.8 Structure of RNA Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. G P S Base is uracil U instead of thymine. P S A G P U S C A P one S C nucleotide ribose
  21. 21. • The 3 types of RNA  Messenger RNA (mRNA) • Produced in the nucleus from DNA template • Carries genetic message to ribosomes  Transfer RNA (tRNA) • Produced in the nucleus from DNA template • Transfers amino acids to ribosomes • Each type carries only one type of amino acid.  Ribosomal RNA (rRNA) • Produced in the nucleolus of the nucleus from DNA template • Joins with proteins to form ribosomes • Ribosomes may be free or in polyribosomes (clusters) or attached to ER.
  22. 22. 11.2 Gene Expression• Early 1900’s, Garrod suggests a relationship between inheritance and metabolic diseases.  First to suggest a link between genes and proteins• DNA provides a blueprint to synthesize proteins.• Central dogma of molecular biology  Information flows from DNA to RNA to protein.
  23. 23. • Transcription  DNA serves as template to make mRNA.• Translation  mRNA directs sequence of amino acids in a protein.  rRNA and tRNA assist
  24. 24. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 11.9 Flow of geneticNucleus CT information CT C A A G G T G G DNA A G A double helix C C T DNA 3′ 5′ C C T C T T A G G Transcription G G A G A A U C C mRNA 5′ 3′Cytoplasm codon mRNA U C C G G A G A A Translation A G G C C U C U U tRNA anticodon Polypeptide Gly Arg Thr
  25. 25. • The genetic code  Translates from nucleic acids to amino acids  Triplet – 3 nucleotide sequence in DNA  Codon- 3 nucleotide sequence in mRNA • A codon encodes a single amino acid. • Start and stop codons
  26. 26. Figure 11.10 Messenger RNA codons Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Second base U C A G UUU UCU UAU UGU U phenylalanine (Phe) tyrosine (Tyr) cysteine (Cys) UUC UCC UAC UGC C U serine (Ser) UUA UCA UAA stop UGA stop A leucine (Leu) UCG UUG UAG stop UGG tryptophan (Trp) G U CUU CCU CAU histidine (His) CGU CUC CCC CAC CGC C C leucine (Leu) proline (Pro) arginine (Arg) Third base CUA CCA CAA CGA A CCG CAG glutamine (Gln) CUG CGGFirst base G AUU ACU AAU AGU U asparagine (Asn) serine (Ser) AUC isoleucine (Ile) ACC AAC AGC C A AUA threonine (Thr) ACA AAA AGA A ACG AAG lysine (Lys) arginine (Arg) AUG methionine (Met) (start) AGG G GUU GCU GAU GGU U aspartic acid (Asp) GUC GCC GAC GGC C G GUA valine (Val) alanine (Ala) glycine (Gly) GCA GAA GGA A GUG GCG GAG glutamic acid (Glu) GGG G
  27. 27. • Transcription  During transcription, complementary RNA is made from a DNA template.  Portion of DNA unwinds and unzips at the point of attachment of RNA polymerase.  Bases join in the order dictated by the sequence of bases in the template DNA strand.
  28. 28. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 11.11 Transcription G to form mRNA C G G C Transcription is taking place— template the nucleotides of mRNA are DNA joined by the enzyme RNA strand polymerase in an order G C G C complementary to a strand of DNA. 3′ RNA G G C polymeraseC C GT U A G G C T G This mRNA transcript is G ready to be processed. G C G C mRNA 5′ to processing
  29. 29. • Newly made pre-mRNA must be processed.  Capping and addition of poly-A tail provide stability.  Introns (non-coding) removed  Leaves only exons (coding)  Alternative splicing can produce different versions of mRNA leading to different proteins.  Now mature mRNA leaves nucleus and associates. with ribosome on cytoplasm.
  30. 30. Figure 11.12 mRNA processing Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. DNA to be transcribed DNA e i e i e transcription poly-A cap tail primary e i e i e mRNA 5′ (cut out) (cut out) 3′ enzyme i i enzyme mature mRNA e = exons i = introns
  31. 31. Figure 11.13 tRNA• Translation structure and function  tRNA brings in amino acids Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Anticodon – group of 3 bases amino acid complementary to a specific codon of mRNA complementary base pairing  After translation is complete, a protein contains the sequence of amino acids originally specified in the DNA. U G G anticodon a. tRNA–amino acid
  32. 32. • Ribosomes are composed of protein and rRNA.  Site of translation – protein synthesis  Binds mRNA and 2 tRNA molecules • P site for a tRNA attached to a peptide • A site for newly arrived tRNA with an amino acid
  33. 33. Figure 11.13 continued Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. tRNA binding sites P site A site large subunit mRNA binding small subunit site b. Ribosome peptide U U U anticodon U G G A C C A A A mRNA 5′ 3′ ribosome c. tRNA–amino acid at ribosome
  34. 34. Figure 11.14 Polyribosome structure and function Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 3′ mRNA codon 5′ a. • Polyribosome – several ribosomes attach to 400,000 b. and translate the same piece of mRNA. b: Courtesy Alexander Rich
  35. 35. • 3 phases of translation 1. Initiation 2. Elongation 3. Termination• Initiation • mRNA binds to small subunit of ribosome. • Large subunit then joins
  36. 36. Figure 11.15 Initiation Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. amino acid methionine initiator tRNA mRNA small ribosomal subunit start codon P site A site large ribosomal subunit mRNA 5′ 3′
  37. 37. • Elongation • Peptide lengthens one amino acid at a time.• Termination • 1 of 3 stop codons reached • Release factor causes ribosomal subunits and mRNA to dissociate. • Complete polypeptide released
  38. 38. Figure 11.16 Elongation cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Elongation 1. tRNA in P site bears growing polypeptide. codon P site A site 5′ 3′ 1 anticodon
  39. 39. Figure 11.16 Elongation cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Elongation peptide 2. This tRNA passes peptide 2 to tRNA in A site. codon P site A site 5′ 3′ 1 anticodon
  40. 40. Figure 11.16 Elongation cycle • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Elongation peptide 3. Empty tRNA leaves P site. 2 new peptide bond codon 3 P site A site 5′ 3′ 1 anticodon
  41. 41. Figure 11.16 Elongation cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Elongation peptide 4. Translocation – 2 ribosome moves forward one codon.  tRNA-peptide now in P site and new A site open for peptide new tRNA bond codon 3P site A site 5′ 3′ 1 anticodon 4
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  43. 43. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Transcription 1. DNA in nucleus serves as a template. 3. mRNA moves into 2. Pre-mRNA is cytoplasm and becomes amino processed associated with acidsDNA before leaving ribosomes. the nucleus. large and small introns tRNA ribosomal subunits 4. tRNAs with peptide primary anticodons mRNA carry amino mature 6. Polypeptide acids to mRNA. anticodon mRNA mRNA synthesis takes place one amino 5. Anticodon–codon acid at a time. complementary base pairing occurs. Translation ribosome codon 8. At termination, the ribosome detaches from 7. When a ribosome the ER; ribosomal subunits attaches to rough ER, and the mRNA dissociate. the polypeptide enters its lumen, where the polypeptide folds and is modified further.
  44. 44. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Transcription amino acidsDNA large and small introns tRNA ribosomal subunits peptide primary mRNA mature anticodon mRNA mRNA Translation ribosome codon
  45. 45. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Transcription 1. DNA in nucleus serves as a template. amino acidsDNA large and small introns tRNA ribosomal subunits peptide primary mRNA mature anticodon mRNA mRNA Translation ribosome codon
  46. 46. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Transcription 1. DNA in nucleus serves as a template. 2. Pre-mRNA is amino processed acidsDNA before leaving the nucleus. large and small introns ribosomal subunits tRNA peptide primary mRNA mature anticodon mRNA mRNA Translation ribosome codon
  47. 47. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Transcription 1. DNA in nucleus serves as a template. 3. mRNA moves into cytoplasm and becomes amino 2. Pre-mRNA is associated with acids processedDNA ribosomes. before leaving the nucleus. large and small introns tRNA ribosomal subunits peptide primary mRNA mature anticodon mRNA mRNA Translation ribosome codon
  48. 48. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Transcription 1. DNA in nucleus serves as a template. 3. mRNA moves into cytoplasm and becomes amino 2. Pre-mRNA is associated with acids processedDNA ribosomes. before leaving the nucleus. large and small introns ribosomal subunits tRNA 4. tRNAs with peptide primary anticodons mRNA carry amino mature acids to mRNA. anticodon mRNA mRNA Translation ribosome codon
  49. 49. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Transcription 1. DNA in nucleus serves as a template. 3. mRNA moves into 2. Pre-mRNA is cytoplasm and becomes amino processed associated with acidsDNA before leaving ribosomes. the nucleus. large and small introns ribosomal subunits tRNA peptide 4. tRNAs with primary anticodons mRNA carry amino mature acids to mRNA. anticodon mRNA mRNA 5. Anticodon–codon complementary base pairing occurs. Translation ribosome codon
  50. 50. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Transcription 1. DNA in nucleus serves as a template. 3. mRNA moves into cytoplasm and becomes amino 2. Pre-mRNA is associated with acids processedDNA ribosomes. before leaving the nucleus. large and small introns tRNA ribosomal subunits 4. tRNAs with peptide primary anticodons mRNA carry amino mature 6. Polypeptide anticodon acids to mRNA. mRNA mRNA synthesis takes place one amino 5. Anticodon–codon acid at a time. complementary base pairing occurs. Translation ribosome codon
  51. 51. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Transcription 1. DNA in nucleus serves as a template. 3. mRNA moves into 2. Pre-mRNA is cytoplasm and becomes amino processed associated with acidsDNA before leaving ribosomes. the nucleus. large and small introns ribosomal subunits tRNA peptide 4. tRNAs with primary anticodons mRNA carry amino mature 6. Polypeptide anticodon acids to mRNA. mRNA mRNA synthesis takes place one amino 5. Anticodon–codon acid at a time. complementary base pairing occurs. Translation ribosome codon 7. When a ribosome attaches to rough ER, the polypeptide enters its lumen, where the polypeptide folds and is modified further.
  52. 52. Figure 11.17 Summary of gene expression in eukaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Transcription 1. DNA in nucleus serves as a template. 3. mRNA moves into 2. Pre-mRNA is cytoplasm and becomes amino processed associated with acidsDNA before leaving ribosomes. the nucleus. large and small introns tRNA ribosomal subunits 4. tRNAs with peptide primary anticodons mRNA carry amino mature 6. Polypeptide acids to mRNA. anticodon mRNA mRNA synthesis takes place one amino 5. Anticodon–codon acid at a time. complementary base pairing occurs. Translation ribosome codon 8. At termination, the ribosome detaches from 7. When a ribosome the ER; ribosomal subunits attaches to rough ER, and the mRNA dissociate. the polypeptide enters its lumen, where the polypeptide folds and is modified further.
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  54. 54. • Gene mutation  Change in the sequence of bases in a gene  Causes • Replication error  Rare due to proofreading • Transposons  “Jumping genes” – pieces of DNA that move within and between chromosomes • Mutagens  Environmental influences – radiation  Chemical mutagens  Repair enzymes
  55. 55. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 11.18 Transposons a. Normal gene Mutated gene transposon codes for cannot code purple for purple pigment pigment purple kernel white kernelb. c. a: Courtesy of Cold Spring Harbor Laboratory
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  57. 57. • Types and effects of mutations  Many mutations go undetected – no observable effect.  Point mutations • Change in single DNA nucleotide • Results can be minor or severe • Sickle cell disease  Frameshift mutations • Extra or missing nucleotides • Usually much more severe • All downstream codons affected • THE CAT ATE THE RAT – C removed • THE ATA TET HER AT
  58. 58. 11.3 DNA Technology• Genetic engineering – inserting cloned genes into an organism  Transgenic organism  Cloning genes – making identical copies• Because the genetic code is nearly universal, it’s possible to transfer cloned genes between virtually any organism.
  59. 59. • Recombinant DNA technology  Recombinant DNA Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (rDNA) contains DNA from 2 or more different DNA duplex A G A A T T C G C T C T T A A G C G organisms. restriction  A vector is used to carry enzyme the foreign DNA. • May be a plasmid from A A T T C G C bacteria “sticky ends” G C G A G  Restriction enzymes are T C T T A A molecular scissors • Cut DNA at specific sites • “Sticky ends”  DNA ligase used to join pieces of DNA together
  60. 60. • Human insulin made by bacterial cells  Human gene removed  Inserted into plasmid  Plasmid inserted into bacteria  Bacteria produce insulin as if it was one of their own gene products.
  61. 61. Figure 11.19 Recombinant DNA technology Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Insulin plasmid DNA gene human cell bacterial host cell cut with restriction enzyme insulin gene plasmid DNA add DNA ligase recombinant DNA bacterial host cell cell multiplies; produces insulin insulin cloned genes for insertion into another host cell insulin © SIU/Visuals Unlimited
  62. 62. Figure 11.19 continued Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. recombinant DNA bacterial host cell cell multiplies; produces insulin insulin cloned genes for insertion into another host cell insulin
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  64. 64. • Transgenic organisms  Biotechnology – use of natural biological systems to create a product  Organisms can be genetically engineered for use in biotechnology.  Transgenic bacteria • Grown in bioreactors • Gene product collected from growth medium  Transgenic plants and animals • Cotton, corn and potato make their own insecticide. • Soybeans herbicide resistant • Larger fishes, cows and pigs from inserted growth hormone gene • “Pharming” – use of transgenic farm animal to produce pharmaceuticals in milk. • Transgenic animals may be cloned – nucleus from adult cell introduced into enucleated egg cell produces identical genotype of adult donor.
  65. 65. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 11.20 Use of transgenic organisms a. b. c. a. Transgenic bacteria in bioreactors b. Salmon grow larger with growth hormone gene. c. Unblemished peas d. have a pest inhibitor gene. d. Transgenic bacteria used for oil cleanup e. Transgenic corn can resist herbicides to e. increase crop yield.a: © Nita Winter; b: Courtesy Robert H. Devlin, Fisheries and Oceans Canada; c: © Richard Shade; d: © Jerry Mason/Photo Researchers, Inc.; e: © AGStockUSA, Inc./Alamy
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  67. 67. • Polymerase chain reaction (PCR)  Amplifies specific DNA sequences  DNA polymerase – makes DNA • From Thermus aquaticus – tolerates high temperatures  Primers – specific DNA segment to be amplified • Doesn’t amplify all DNA – only target  Cycles over and over again doubling amount of DNA at each cycle
  68. 68. Figure 11.21 Polymerase chain reaction Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. DNA from one homologue DNA polymerase, First cycle 5′ 3′ primers, 3′ 5′ nucleotides 5′ 3′ Heating separates strands 3′ 5′ Cooling allows primers 5′ 3′ to base pair at target site 3′ 5′ and for DNA polymerase 5′ 3′ to make new DNA 3′ 5′ end of first cycle 5′ 3′ 3′ 5′ to second cycle 5′ 3′ 3′ 5′
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  70. 70. • DNA fingerprinting  Makes use of repeating noncoding DNA segments  People differ in how many repeats.  Can use PCR to increase amount of DNA sample  Electrophoresis separates samples by size. • Longer DNA strands are larger and migrate less on the gel.
  71. 71. Figure 11.22 DNA fingerprinting Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Collect DNA crime scene suspect suspect evidence A B 12 repeats 12 repeats 12 repeats 16 repeats 16 repeats 12 repeats Perform PCR on repeats Use gel electrophoresis to identify criminals
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  73. 73. 11.4 Genomic and Proteomics• Genomics – study of genomes  Human and other organisms  Coding and noncoding segments• Human Genome Project  13-year effort  Found many small regions of DNA vary among individuals  Some individuals even have extra copies of genes.  Differences may have no effect or may increase or decrease susceptibility to disease.
  74. 74. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 11.23 Variations in DNA Met Pro polypeptide sequence 5 3 mRNA A U G C C C T A C G G G 3 5 template DNA strand Gene A Gene B Gene C A T G C C C G T C T C A T A C G G G C A G A G T Intergenic DNA Intergenic DNAa. Normal chromosomal DNA Met Thr polypeptide 5 3 mRNA A U G A C C T A C T G G 3 5 template DNA strand Gene A Gene B Gene C A T G A C C G T C T C A T A C T G G C A G A G T Intergenic DNA Intergenic DNAb. Variation in the order of the bases within a gene due to a mutation Gene A Gene B Gene C A T G C C C G T C G C A T A C G G G C A G C G T Intergenic DNA Intergenic DNAc. Variation in the order of the bases within an intergenic sequence due to a mutation Gene A Gene B Gene B Gene C A T G C C C G T C T C A T A C G G G C A G A G T Intergenic DNA Intergenic DNA Intergenic DNAd. Variation in the gene copy number
  75. 75. • Genome comparisons  Clues to evolutionary origins  Genes of humans and chimps 98% alike • Humans and mice 85% alike • Humans also share genes with bacteria  Comparing human and chimp chromosome 22 • Among the genes that differed were several that may have played a role in human evolution.  Speech, hearing and smell • Comparing genomes may be a way of finding genes associated with human diseases.
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  77. 77. Figure 11.24 Studying genomic differences between chimpanzees and humans Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. b. c. a(both), b(left): © Getty RF; b(right): © The McGraw-Hill Companies/Bob Coyle, photographer; c(both): © Getty RF
  78. 78. Figure 11.25 Bioinformatics• Proteomics – explores structure and function of cellular proteins and how they interact to produce traits  Important in drug development• Bioinformatics – application of computer technologies to study genome and proteome  Using computer to analyze large amount of data to find significant patterns

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