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Cenancestor (aka MRCA or LUCA) as placed by ancient duplicated genes (ATPases, Signal recognition particles, EF) The “Root” strictly bifurcating no reticulation only extant lineages based on a single molecular phylogeny branch length is not proportional to time The Tree of Life according to SSU ribosomal RNA (+) PHYLOGENY: from Greek phylon, race or class, and -geneia, born. “the origin and evolution of a set of organisms, usually of a species” (Wikipedia);
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Tree, Web, or Coral of Life? Charles Darwin Photo by J. Cameron, 1869 Page B26 from Charles Darwin’s (1809-1882) notebook (1837) “The tree of life should perhaps be called the coral of life, base of branches dead”
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Which Type of Coral?
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Darwin’s coral was a red algae (Bossea orbignyana) From Florian Maderspacher: “The captivating coral--the origins of early evolutionary imagery.” Curr Biol 16: R476-8 2006 The captivating coral. According to the ideas of Horst Bredekamp, parts of the diagram in Darwin's origin of species (centre) more or less directly reflect the branching properties of a specimen Darwin collected himself.
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The Coral of Life (Darwin)
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Gene Transfer and Phylogenetic Reconstruction: Friends or Foes? Popular view Gene transfer is a disruptive force in phylogenetic reconstruction. New view Events of ancient gene transfer are valuable tools for reconstructing organismal phylogeny.
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1. Any ancient gene transfer to the ancestor of a major lineage implicitly marks the recipient and descendents as a natural group. 2. The donor must exist at the same time or earlier than the recipient. Ancient HGTs
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Gene “ping-pong” between different lineages can be used to build correlations between different parts of the tree/net of life. Presence of a transferred gene is a shared derived character that can be useful in systematics.
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The central dogma Why might this be wrong or incomplete
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Replication lagging and leading strand - strand bias
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Transcription
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Prokaryotes Eukaryotes
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RNA processing Intron types RNA can be the catalyst Simple illustration of a pre-mRNA, with introns (top). After the introns have been removed via splicing, the mature mRNA sequence is ready for translation (bottom).
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RNA enzymes:
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Ribosome
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Self-splicing introns
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Group II intron
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The RNA world concept What arguments support an “RNA world” preceding a two biopolymer world?
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Protein structure:
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Angles in the protein backbone
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spdbf - viewer aka Deep View Free and powerful program Steep learning curve Interacts with modeling server available at http://ca.expasy.org/ http://spdbv.vital-it.ch/http://ca.expasy.org/ http://spdbv.vital-it.ch/ Gale Rhodes’ Tutorial is at http://www.usm.maine.edu/~rhodes/SP VTut/index.html http://www.usm.maine.edu/~rhodes/SP VTut/index.html
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Simplify the display Show only alpha carbons Color secondary structure Turn 3 D display on
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1HEW Backbone as ribbon Sidechains only in binding pocket Substrate in yellow Non-polar residues of binding pocket in turquoise
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mind map 1
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mind map 2
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