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Horizontal Gene Transfer and the Last Universal Common Ancestor •

Horizontal Gene Transfer and the Last Universal Common Ancestor • The Open University • 5th and 6th September 2013. Coupling between information processing and redox chemistry. Cellular co-location of energy transduction with genome function John F. Allen

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Horizontal Gene Transfer and the Last Universal Common Ancestor •

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  1. Horizontal Gene Transfer and the Last Universal Common Ancestor • The Open University • 5th and 6th September 2013 Coupling between information processing and redox chemistry. Cellular co-location of energy transduction with genome function John F. Allen School of Biological and Chemical Sciences, Queen Mary University of London and Research Department of Genetics, Evolution and Environment, University College London 1

  2. http://en.wikipedia.org/wiki/Geologic_time_scale

  3. LUCA here seems to mean: The Last Common Ancestor of all things alive today... ...therefore Horizontal Gene Transfer could have occurred between LUCA and things now no longer alive

  4. What do we mean by LUCA...? A. The Last Common Ancestor of all things alive today (on Earth)... B. The Last Common Ancestor of all things that have ever lived (on Earth)...

  5. This tree diagram, used to show the divergence of species, is the only illustration in the Origin of Species. http://en.wikipedia.org/wiki/On_the_Origin_of_Species

  6. LUCA here must mean: B. The Last Common Ancestor of all things that have ever lived... ...in which case... • With what did LUCA engage in Horizontal Gene Transfer...? • Can any sensible distinction be made between LUCA’s Horizontal and Vertical Gene Transfer...? • Can Horizontal Gene Transfer have played any part in the Origin of Life?

  7. Coupling between information processing and redox chemistry. Electron transport – chains of coupled oxidation and reduction reactions

  8. Coupling between information processing and redox chemistry. Homeostasis... ...the maintenance of a constant internal environment despite changes in the external environment.

  9. A block diagram for feedback. The feedback is negative if B < 0 http://en.wikipedia.org/wiki/Feedback

  10. Coupling between information processing and redox chemistry. Redox Homeostasis... ...the maintenance of a constant electrochemical potential and ionic concentration gradient across a cellular boundary, despite changes in the electrochemical potential of the external environment and despite changing identities and activities of electron donors and acceptors. Allen JF (2010) Journal of Cosmology, 10, 3362-3373

  11. A feedback loop involving the elements of a redox repressor or activator incorporating an iron-sulphur centre in a polypeptide Allen J. F. (2010) Journal of Cosmology, 10, 3362-3373

  12. A feedback loop involving the elements of a two-component redox regulatory system Allen J. F. (2010) Journal of Cosmology, 10, 3362-3373

  13. B. The proton motive force of living cells descended from LUCA.  The pmf is made by an alkaline (high pH) cytoplasm and by an acidic (low pH) extracellular environment.  The gradient is continuously replenished by electrons flowing across the membrane from donors to acceptors. A. The proton motive force across the boundary of LUCA.  The pmf is made by an alkaline (high pH) internal effluent from LUCA's founding hydrothermal vent and by an acidic (low pH) external environment of carbonic acid solution. Nick Lane, John F. Allen and William Martin (2010) How did LUCA make a living? Chemiosmosis in the origin of life. Bioessays 32: 271-280

  14. Steps from a porous inorganic metal-sulphide vesicle to a free-living cell. A. Hydrothermal fluid is alkaline, in contrast to the acidic ocean into which it flows through the boundary of a porous, catalytic, metal sulphide vesicle.

  15. Steps from a porous inorganic metal-sulphide vesicle to a free-living cell. B. The porosity of the vesicle is decreased by the intrusion of products of autocatalytic carbon reduction, symbolized by the cycle of carbon. The boundary of the vesicle begins to sustain a small gradient of hydrogen ion concentration and electrical potential difference: positive (P-phase) outside; negative (N-phase) inside.

  16. Steps from a porous inorganic metal-sulphide vesicle to a free-living cell. C. The porosity decreases further. A mechanism of negative feedback interrupts proton influx, and an active transport drives proton efflux.

  17. Steps from a porous inorganic metal-sulphide vesicle to a free-living cell. D. The vesicle is now formed from the organic intrusion alone, which presents a sufficient barrier to proton influx for the active proton efflux to generate and sustain a proton motive force. The dependency on hydrothermal fluid is lost, along with the inorganic container, though remnants of the latter remain to support vectorial electron and proton translocation.

  18. Steps from a porous inorganic metal-sulphide vesicle to a free-living cell. Allen JF (2010) Redox homeostasis in the emergence of life. On the constant internal environment of nascent living cells. Journal of Cosmology, 10, 3362-3373

  19. Coupling between information processing and redox chemistry. Cellular co-location of energy transduction with genome function Photosynthesis and respiration

  20. N –ve N –ve P +ve P +ve

  21. P +ve N –ve After: David S. Goodsell (1993) The Machinery of Life. Springer

  22. N –ve P +ve

  23. P +ve N –ve N –ve Allen, J. F. (1993) Control of Gene Expression by Redox Potential and the Requirement for Chloroplast and Mitochondrial Genomes. Journal of Theoretical Biology, 165, 609-631

  24. Coupling between information processing and redox chemistry. Cellular co-location of energy transduction with genome function Co-location for Redox Regulation Allen, J. F. (2003) The function of genomes in bioenergetic organelles. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 358, 19-37 jfallen.org/corr

  25. Allen J. F., de Paula W. B. M., Puthiyaveetil S. & Nield J. (2011) Trends in Plant Science 16(12), 645-655

  26. Coupling between information processing and redox chemistry. Cellular co-location of energy transduction with genome function The Redox Switch Hypothesis for the first cyanobacterium and for the origin of oxygenic photosynthesis

  27. Allen J. F. (2005) A redox switch hypothesis for the origin of two light reactions in photosynthesis. FEBS Letters 579: 963-968

  28. Archean landscape by Peter Sawyer of the Smithsonian Institution

  29. Phanerozoic Landscape Stromatolites at Hamelin Pool, Western Australia Photograph 4 October 2007 by Catherine Colas des Francs-Small, The University of Western Australia

  30. Policeman Point, Coorong Lagoon, South Australia Photograph 9 March 2009 by the author

  31. Policeman Point, Coorong Lagoon, South Australia Photograph 9 March 2009 by the author

  32. Dietrich, L.E.P., Tice, M.M. and Newman, D.K. (2006) The co-evolution of life and Earth. Current Biology 16, R396-R400

  33. http://en.wikipedia.org/wiki/Geologic_time_scale

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