Discussion Meeting

Comparative functional genomics of chloroplasts, mitochondria and their bacterial homologues - new perspectives on symbiosis in cell evolution

The Royal Society of London
Wednesday 26th and Thursday 27th June 2002

Update January 2003

Update December 2002

Update October 2002

Update July 2002

  • Thanks to all concerned for a great meeting, especially to Suzi White and the staff at the Society.
  • The BBC Radio 4 programme, The Material World, June 27th, covered the meeting and has a web page. The programme can be also be heard as a Real Audio stream linked from here.

Who could participate?

Royal Society Discussion Meetings are open to all, though prior registration is required. Registration is free.

Who were the speakers?

  • John Allen, Lund University, Sweden
  • Carl Bauer, Indiana University, Bloomington, Indiana, USA
  • Axel Brennicke, University of Ulm, Germany
  • Tom Cavalier-Smith, University of Oxford
  • W. Ford Doolittle, Dalhousie University, Canada
  • John Gray, University of Cambridge
  • Reinhold Herrmann, Ludwig Maximilian's University, Munich, Germany
  • Chris Howe, University of Cambridge
  • Siv Andersson, Uppsala University, Sweden
  • William Martin, Heinrich Heine University, Düsseldorf, Germany
  • Martin Embley, Natural History Museum, London
  • John Raven, University of Dundee
  • Louis Tielens, Utrecht University, The Netherlands
  • Iain Wilson, MRC National Institute for Medical Research

Who were the chairmen?

  • John Allen, Lund University, Sweden
  • Angela Douglas, University of York
  • Chris Leaver, University of Oxford
  • John Raven, University of Dundee
  • Bob Whatley, University of Oxford

How may one obtain further information?

Are the proceedings of the meeting published?

Yes. The proceedings will are published, together with a transcript of the discussion that follows each talk, as an issue of Philosophical Transactions of the Royal Society, Series B: Biological Sciences. See http://www.pubs.royalsoc.ac.uk/phil_bio/phil_bio.html

Which topics were discussed?

  • The evolutionary origin of eukaryotic cells
  • Mitochondrial genomes and gene function
  • Plastidic genomes and gene function
  • Hydrogenosomes
  • Prokaryotic homologues of organelles
  • Selective forces determining the composition of organellar genomes
  • Metabolic division of labour between organelles and the cytosol
  • Informational division of labour between organelles, nucleus, and cytoplasm
  • Evolution of regulatory processes in photosynthesis and respiration

Why were these appropriate topics for discussion?

The "endosymbiont hypothesis" for the origin of plastids and mitochondria is widely accepted, but recent findings, especially those stemming from advances in comparative genomics, call into question many of its associated assumptions. For mitochondria, the conventional picture of a single, ancestral, endocytotic event between an aerobic, α-proteobacterium and a hypothetical host cell, assumed to be anaerobic and fermentative, is unlikely to be correct. A primary objective of the meeting will be to revise the endosymbiont hypothesis to make it compatible with the wide diversities of organellar genomes and the greatly enlarged range of specialised metabolic and bioenergetic contributions they make to the life of eukaryotic cells.

Which new developments were discussed?

The proposal that hydrogen, rather than ATP, was the basis of the symbiosis that gave rise to mitochondria. The diversity of respiratory functions in mitochondria and hydrogenosomes. Hydrogenosomes with and without genomes. Complete genomes of organelles and prokaryotes. Complete genomes of eukaryotes where organelle-targeted gene products can be identified. Redox regulation of gene expression as the function of organellar genomes. Non-photosynthetic plastids and non-aerobially respiring mitochondria. Free-radical mutagenesis and Müller's ratchet as selective advantages of nuclearly-located genes. Mechanisms and pathways of protein import into chloroplasts and mitochondria

Why are these developments important?

Recent progress in all these areas has been rapid. The topics are timely since, together, they call for a re-evaluation of the endosymbiont hypothesis, a central tenet of evolutionary cell biology. A new synthesis, compatible with recent findings, will have great explanatory and predictive value, extending beyond evolutionary theory, to many areas of biology, medicine and agriculture. Genomics has now raced far ahead of our understanding of why genetic compartmentation exists in eukaryotic cells, how it arose, and what it means. This discussion meeting will encourage a new synthesis of ideas, and will focus on a critical stage in a developing field.

Which fields were brought together?

Geochemistry; the origin of life; molecular biology; cell biology; functional genomics; evolution and phylogeny; bioenergetics (photosynthesis and respiration); microbiology; gene expression; plant, animal, and microbial physiology; physiological ecology.

What is a Royal Society Discussion Meeting?

Discussion Meetings are a long-standing and important part of the Royal Society's promotion of science and its public understanding. A substantial proportion of the time is given to discussion. A schedule of Discussion Meetings can be seen on the web page http://www.royalsoc.ac.uk/events/index.html

Who were the organisers?

John F. Allen
Professor of Plant Cell Biology
Plant Biochemistry
Lund University
Box 124
SE-221 00 Lund
Tel: +46 46 222 7788
Fax: +46 46 222 4009
John A. Raven, FRS, FRSE
Boyd Baxter Professor of Biology
Department of Biological Sciences
University of Dundee
Millers Wynd
Dundee DD1 4HN
Scotland, UK
Tel: +44 1382 344281
Fax: +44 1382 344275

Related discussion meeting

Molecular evolution of photosynthesis and respiration, The Novartis Foundation, London, Friday, 28th June 2002

Related links

Valid HTML 4.01!