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BiS2C: Lecture 10: Not Trees

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Slides for BIs2C at UC Davis Spring 2016.
Lecture by Jonathan Eisen.
Topic: The Tree of Life.

Publicado en: Ciencias
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BiS2C: Lecture 10: Not Trees

  1. 1. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Lecture 10: Not Trees BIS 002C Biodiversity & the Tree of Life Spring 2016 Prof. Jonathan Eisen 1
  2. 2. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Where we are going and where we have been • Previous Lecture: !9: Microbial Diversity • Current Lecture: !10: Not trees • Next Lecture: !11: Functional Diversity 2
  3. 3. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Not Trees 3
  4. 4. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Key Concepts • Different parts of a cell or genome can have different histories • Many cases and causes of this including • Viral insertion of DNA and movement between hosts • Lateral gene transfer (unidirectional movement of DNA from one cell to another) • Endosymbiosis (one cell bringing another cell inside of it) • Detecting such events can be done via phylogenetic analysis 4
  5. 5. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Diverse Organelles 5 Mitochondrion Chloroplast Nucleus
  6. 6. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 8 Many similarities to bacteria / archaea Mitochondria look like bacteria But morphology not useful for phylogeny of bacteria & archaea
  7. 7. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 9 DNA Mitochondria have their own genomes
  8. 8. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Woese Tree of Life 10 rRNA rRNArRNA ACUGC ACCUAU CGUUCG ACUCC AGCUAU CGAUCG ACCCC AGCUCU CGCUCG Taxa Characters S ACUGCACCUAUCGUUCG R ACUCCACCUAUCGUUCG E ACUCCAGCUAUCGAUCG F ACUCCAGGUAUCGAUCG C ACCCCAGCUCUCGCUCG W ACCCCAGCUCUGGCUCG Taxa Characters S ACUGCACCUAUCGUUCG E ACUCCAGCUAUCGAUCG C ACCCCAGCUCUCGCUCG B AMito B
  9. 9. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 12 Phylogenetic Tree of Mitochondrial Genes
  10. 10. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Phylogenetic Tree of Mitochondrial Genes 13
  11. 11. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Eukaryote Groups - More Detail 1414
  12. 12. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Phylogenetic Tree of Mitochondrial Genes 15 Conclusion: All Mitochondria Have a Common Ancestry
  13. 13. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 One Theory of Mitochondrial Evolution 16
  14. 14. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 A common ancestor of eukaryotes 17 Cell membrane Genome
  15. 15. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 18 αProteo Genome Bacterial cell envelope Cell membrane Genome A Symbiosis with a Proteobacterium
  16. 16. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Engulfment 19 αProteo Cell membrane Genome Genome Bacterial cell envelope
  17. 17. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 20 αProteo Cell membrane Genome Genome Bacterial cell envelope Host membrane Endosymbiosis Endosymbiosis: when an organism (the host) bring another organism (the symbiont) inside of its cell.
  18. 18. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 21 αProteo Cell membrane Genome Genome Bacterial cell envelope Host membrane Endosymbiosis Endosymbiosis: when an organism (the host) bring another organism (the symbiont) inside of its cell. Is a “Primary symbiosis” because symbiont has not experienced a prior symbiosis
  19. 19. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Origin of the nucleus 22 N αProteo Host membrane Nucleus Cell membrane Genome Genome Bacterial cell envelope
  20. 20. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Mitochondria 23 N Mitochondrion Genome M Nucleus Cell membrane Genome
  21. 21. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Different histories within one genome 24 Bacteria Archaea Eukaryotes Nucleus Mitochondrion A model of a eukaryotic cell Nuclear Tree Mitochondrial Tree Eukaryotes Bacteria ArchaeaB
  22. 22. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Chimeras 25 Bacteria Archaea Eukaryotes Nucleus Mitochondrion A model of a eukaryotic cell Nuclear Tree Mitochondrial Tree Eukaryotes Bacteria ArchaeaB
  23. 23. N M N M N M N M N M N M N M N M N + + + + - + + + + Presence/Absence of Mitochondria • How Explain Pattern of Presence / Absence?
  24. 24. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Excavates: Diplomonads and Parabisalids • Unicellular • Lack mitochondria and most are anaerobic. This is a derived condition • Giardia lamblia - a diplomonad - is a human parasite • Trichomonas vaginalis - parabasalid - STD 27
  25. 25. N M N M N M N M N M N M N M N M N + + + + - + + + + Mitochondria found throughout eukaryotic diversity in almost all taxa Phylogeny of mitochondria suggest all have a common origin Phylogeny of mitochondria is congruent to phylogeny of nucleus from same taxa
  26. 26. Mitochondria found throughout eukaryotic diversity in almost all taxa N M N M N M N M N M N M N M N M N + + + + - + + + + Phylogeny of mitochondria suggest all have a common origin Phylogeny of mitochondria is congruent to phylogeny of nucleus from same taxa Can infer then that mitochondria were likely present in the common ancestor of all eukaryotes. N M
  27. 27. Mitochondria found throughout eukaryotic diversity in almost all taxa N M N M N M N M N M N M N M N M N + + + + - + + + + Phylogeny of mitochondria suggest all have a common origin Phylogeny of mitochondria is congruent to phylogeny of nucleus from same taxa Can infer then that mitochondria were likely present in the common ancestor of all eukaryotes. N M N M N M N M N M N M
  28. 28. Mitochondria found throughout eukaryotic diversity in almost all taxa N M N M N M N M N M N M N M N M N + + + + - + + + + Phylogeny of mitochondria suggest all have a common origin Phylogeny of mitochondria is congruent to phylogeny of nucleus from same taxa Can infer then that mitochondria were likely present in the common ancestor of all eukaryotes. N M N M N M N M N M N M Then can infer that lineages w/o mitochondria lost them sometime in their history
  29. 29. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Phylogenetic Tree of Mitochondrial Genes 36 Some species have mitochondrially related genes even though they do not have mitochondria
  30. 30. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Different histories within one genome 37 Bacteria Archaea Eukaryotes Nucleus Mitochondrion A model of a eukaryotic cell Nuclear Tree Mitochondrial Tree Eukaryotes Bacteria ArchaeaB
  31. 31. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Case 2: Chloroplast Evolution 38
  32. 32. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Scattered distribution of chloroplasts 3939
  33. 33. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Copying the Mitochondrial Model … 40
  34. 34. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Eukaryotic Cell 41 N M Mitochondrion Mitochondrial Genome Nucleus Cell membrane Nuclear Genome
  35. 35. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Symbiosis with Free Living Cyanobacterium 42 N Mitochondrion Mitochondrial Genome M Nucleus Cell membrane Nuclear Genome Cyanobacterial Cell envelope Cyanobacterial Genome Cyano
  36. 36. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Engulfment 43 N Mitochondrion Mitochondrial Genome M Nucleus Cell membrane Nuclear Genome Cyanobacterial Cell envelope Cyanobacterial Genome Cyano
  37. 37. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Endosymbiosis 44 N Mitochondrion Mitochondrial Genome M Nucleus Cell membrane Nuclear Genome Cyanobacterial Cell envelope Cyanobacterial Genome Cyano Is a “Primary symbiosis” because the symbiont has not experienced a prior symbiosis.
  38. 38. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Chloroplast 45 N Mitochondrion Mitochondrial Genome M Nucleus Cell membrane Nuclear Genome Chloroplast Cell envelope Chloroplast Genome Chloroplast
  39. 39. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Membrane lost in some 46 N Mitochondrion Mitochondrial Genome M Nucleus Cell membrane Nuclear Genome Outer cell membrane lost in some Chloroplast Genome Chloroplast
  40. 40. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Cell wall lost in some 47 N Mitochondrion Mitochondrial Genome M Nucleus Cell membrane Nuclear Genome Cell wall lost in some Chloroplast Genome Chloroplast
  41. 41. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 48 N Mitochondrion Mitochondrial Genome M Nucleus Cell membrane Nuclear Genome Cell wall lost in some Chloroplast Genome Chloroplast If this model is correct, what should phylogenetic trees of genes from the chloroplast look like?
  42. 42. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 If single origin what should trees look like? 49
  43. 43. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 50 Bacteria Archaea Eukaryotes Model prediction 1 Predicted tree for the nuclear genome
  44. 44. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 51 Bacteria ArchaeaEukaryotes Predicted tree for the chloroplast genome Bacteria Model prediction 2
  45. 45. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 What if chloroplast had many separate origins? 52
  46. 46. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 53 Bacteria ArchEuks Alternative model: multiple origins of chloroplasts Possible tree for alternative model Bact Euks Euks
  47. 47. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Testing the models 54
  48. 48. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 55 Testing the models: morphology not informative Many similarities to bacteria / archaea
  49. 49. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 56 DNA Testing the models: use DNA
  50. 50. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Chloroplast Phylogeny 57
  51. 51. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Chloroplast Phylogeny 58
  52. 52. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Chloroplast Phylogeny 59 Conclusion: All Chloroplasts Have a Common Ancestry
  53. 53. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Different histories within one genome Nucleus CPST MITO Chloroplast Tree Bacteria Archaea Eukaryotes Nuclear Tree Mitochondrial Tree Eukaryotes Bacteria ArchaeaB Bacteria BEukaryotes Archaea
  54. 54. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Different histories within one genome Nucleus CPST MITO Chloroplast Tree Bacteria Archaea Eukaryotes Nuclear Tree Mitochondrial Tree Eukaryotes Bacteria ArchaeaB Bacteria BEukaryotes Archaea
  55. 55. Why does it matter which lineage they came from? Many photosynthetic bacteria Chloroplast biology is more similar to that of cyanobacteria than to other photosynthetic bacteria
  56. 56. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 But …. 66
  57. 57. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Model Has Limitations N M N M N M N M N M N M Archaea Eukarya Bacteria LUCA NM NM NM NM NM NM Model like this is inconsistent with much of the data C C C C C C 67
  58. 58. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Scattered distribution of chloroplasts 6868
  59. 59. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M C N M C N M C N M C N M C N M C Scattered distribution of chloroplasts 69 Hypothesis 1: Ancestral AND Loss
  60. 60. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M C N M C N M C N M C N M C N M C Scattered distribution of chloroplasts 70 Hypothesis 1: Ancestral AND Loss If correct, then tree of chloroplasts should still parallel tree of nuclear genome (with some organisms missing). But it does not.
  61. 61. Plantae group only have “simple” membrane around their chloroplasts
  62. 62. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Cryptomonad Some organisms have complicated membranes around their chloroplasts.
  63. 63. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M C N M N M N M N M N M Scattered distribution of chloroplasts 73 Hypothesis 2: Diversification of Major Lineages Symbiosis in Plantae Ancestor
  64. 64. N M C N M C N M C N M C Each lineage accumulates some unique properties, such as sequences of some of their genes (N, M or C genes). N M C N M C N M C N M C N M C
  65. 65. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M C Scattered distribution of chloroplasts 75 Hypothesis 2: Diversification of Major Lineages Symbiosis in Plantae Ancestor “Secondary Symbiosis” in other lineages
  66. 66. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Model for “Secondary” Symbiosis 76
  67. 67. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Symbiosis between two eukaryotic cells 77 N M “Normal” eukaryote Plantae representative with chloroplast N M C
  68. 68. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 78 N M N M C Engulfment
  69. 69. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 79 N M N M C Symbiont Host Endosymbiosis Endosymbiosis: when an organism (the host) bring another organism (the symbiont) inside of its cell.
  70. 70. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 80 N M N M C Symbiont Host This is a “secondary” symbioses because the symbiont itself already was a host of other symbionts. Endosymbiosis
  71. 71. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 81 N M N C Symbiont Host Second mitochondria often lost
  72. 72. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 82 N M C Symbiont Host Second nucleus often lost
  73. 73. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Secondary Symbioses of Euglenas 83
  74. 74. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Excavates: Euglenids • Have flagella. • Some are photosynthetic, some always heterotrophic, and some can switch. 84 Movement in the euglenoid Eutreptia
  75. 75. N M N M N M N M N M N M C NM C NM C NM C N M C N M C N M C N M C N M C Euglena Nuclear DNA tells us what its phylogenetic backbone is 85
  76. 76. Euglena plastid DNA says its plastid is related to those of chlorophytes 86
  77. 77. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 A lonely excavate ... N M 87
  78. 78. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M C N M C N M C N M C N M C N M C N M C N M C N M C N M 88 Engulfment of Chlorophyte
  79. 79. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M N M C 89 Engulfment of Chlorophyte
  80. 80. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M N M C 90 Endosymbiosis
  81. 81. N M N M N M N M N M N M C NM C NM C NM C N M C N M C N M C N M C N M C Phylogenetic analysis of plastid DNA reveals that the eukaryote engulfed by euglena was a Chlorophyte Euglena Nuclear DNA tells us what its phylogenetic backbone is 91
  82. 82. N M N M N M N M N M N M C NM C NM C NM C N M C N M C N M C N M C N M C Phylogenetic analysis of plastid DNA reveals that the eukaryote engulfed by euglena was a Chlorophyte Note - in some cases a “relic” nuclear genome of the symbiont is also still present and this can also be used to determine what type of organism the symbiont was Euglena Nuclear DNA tells us what its phylogenetic backbone is 92
  83. 83. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Secondary Symbioses of Diatoms 93
  84. 84. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Stramenopiles: Diatoms 94 A colony of the diatom, Bacillaria paradoxa •Unicellular, but many associate in filaments. •Have carotenoids and appear yellow or brown. •Excellent fossil record •Most are photoautotrophic •Responsible for 20% of all carbon fixation. •Oil, gas source
  85. 85. N M N M N M N M N M Many lines of evidence indicate that it occurred in the common ancestor of the “Plantae” lineage. One line of evidence for this is that all organisms on this branch have chloroplasts and the cells of these organisms resemble the “primary” symbiotic cell. N M C NM C NM C NM C N M C N M C N M C N M C N M C Diatom nuclear DNA tells us what its phylogenetic backbone is 95
  86. 86. Diatom plastid DNA says its plastid is related to those of red algae 96
  87. 87. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 A lonely stramenophile ... N M 97
  88. 88. N M C N M C N M C N M C N M C N M C N M C N M C N M C N M Engulfment of a red algae 98
  89. 89. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M N M C 99
  90. 90. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M N M C 100
  91. 91. N M N M N M N M N M N M C NM C NM C NM C N M C N M C N M C N M C N M C Phylogenetic analysis of plastid DNA reveals that the eukaryote engulfed by diatoms was a red algae Euglena Nuclear DNA tells us what its phylogenetic backbone is 101
  92. 92. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Secondary Symbioses of Others 102
  93. 93. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M N M N M N M N M N M C NM C NM C NM C NM C NM C NM C NM C NM C Many other secondary endosymbioses Apicomplexans Dinoflagellates Amoebozoans 10
  94. 94. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 •Most are marine and are important photoautotrophic primary producers •Mixture of pigments give them a golden brown color. •Have two flagella, one in an equatorial groove, the other in a longitudinal groove. Alveolates: Dinoflagellates Certium tenue Coral symbiont 104
  95. 95. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Alveolates: Apicomplexans • All parasitic • Have a mass of organelles at one tip —the apical complex that help the parasite enter the host’s cells. 105 Apical complex • Plasmodium falciparum- Malaria kills 700,000-2,000,000 people per year—75% of them are African children 105
  96. 96. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 • Not colonial; live as single cells • Some secrete shells or glue sand grains together to form a casing. • Many pathogens 106 Amoebozoans: Loboseans
  97. 97. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Rhizaria: Cercozoans Some cercozoans are aquatic, others live in soil. They have diverse forms and habitats. One group has chloroplasts derived from a green alga by secondary endosymbiosis. Euglyphid 107 Chlorarachnion reptans
  98. 98. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Still Can’t Fit Model to Some Eukaryotes 108
  99. 99. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Dinoflagellate Kryptoperidinium foliaceum http://onlinelibrary.wiley.com/doi/10.1111/j.1550-7408.2007.00245.x/full 109
  100. 100. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 •All are multicellular; some get very large (e.g., giant kelp). •The carotenoid fucoxanthin imparts the brown color. •Almost exclusively marine. Stramenopiles: Brown Algae 110 A community of brown algae: The marine kelp forest
  101. 101. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M 111 Tertiary Symbioses? “Normal” eukaryote
  102. 102. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M 112 N M N M C Tertiary Symbioses? “Normal” eukaryote Euglenoid
  103. 103. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M Engulfment 113 N M N M C
  104. 104. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M 114 N M N M C Host Symbiont Endosymbsiosis This is a “tertiary” symbiosis because the symbiont itself already underwent a secondary symbiosis.
  105. 105. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 N M N M N M N M N M N M C NM C NM C NM C N M C N M C N M C N M C N M C 115 Tertiary endosymbioses? Brown Algae Tertiary Endosymbsiosis
  106. 106. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Plants and Animals Get Many Functions from Symbionts • Endosymbioses (only really work with eukaryotic cells as hosts) !Legumes with nitrogen fixing bacteria !Aphids with amino acid synthesizing bacteria !Tubeworms with chemosynthetic bacteria !Lichens - fungi with algae or cyanobacteria !100s more • Other symbioses !Cellulose digestion in the guts of termintes, ruminants 116
  107. 107. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Viruses 117
  108. 108. Figure 26.25 Viruses Are Diverse !118
  109. 109. Figure 26.25 Viruses Are Diverse (Part 1) !119
  110. 110. Figure 26.25 Viruses Are Diverse (Part 2) !120
  111. 111. Figure 26.25 Viruses Are Diverse (Part 3) !121
  112. 112. • Where do viruses sit on the tree of life? • Viruses are obligate parasites of other organisms and cannot live on their own • Three main theories about viruses and where they sit on the tree of life • 1. Viruses are relics from a pre-cellular world • 2. Viruses are escaped portions of cellular organisms • 3. Viruses are extremely derived and reduced cellular organisms !122
  113. 113. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 123 Bacteria Archaea Eukaryotes Virus Evolution Model 1: The Fourth Domain Viruses
  114. 114. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 124 Bacteria Archaea Eukaryotes Virus Evolution Model 2: Separate Origin Viruses
  115. 115. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 125 Bacteria Archaea EukaryotesViruses Viruses Virus Evolution Model 3: From Within Other Groups
  116. 116. Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 Probably a Little of Each 126

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