1. Life History Traits and Genome Structure Aerobiosis and G+C Content in Bacteria J.R. Lobry Université Claude Bernard - Lyon I CNRS UMR 5558 & INRIA Helix FRANCE

3. Aerobic versus Anaerobic You need the presence of O 2 to live, you are aerobic (obligate) You need the absence of O 2 to live, you are anaerobic (obligate) [...snip...]

4. Only Anaerobic Species Anaerobic and Aerobic Species

5. Aerobic >> Anaerobic In aerobic conditions (with O 2 ) the oxydation of one molecule of glucose (respiration) yields 38 ATP (metabolic currency unit). Short generation times. In anaerobic conditions (without O 2 ) the fermentation of one molecule of glucose yields 2 ATP (metabolic currency unit). Long generation times. The generation time is a life history trait

6. Life History Traits and Genome Structure Aerobiosis and G+C Content in Bacteria J.R. Lobry Université Claude Bernard - Lyon I CNRS UMR 5558 & INRIA Helix FRANCE

7. Bacteria in the Universal Tree of Life Pseudomonas Escherichia Halobacterium Methanobacterium Desulfurococcus Halococcus Methanococcus Thermoproteus Thermus Anacystis Bacillus Physarum Crithidia Tetrahymena Prorocentrum SaccharomycesOryza Homo Drosophila Streptomyces EUCARYA ARCHAEA EUBACTERIA « BACTERIA » ?

8. Only Bacteria Bacteria and Eucarya

9. Bacterial Genomes: Circular dsDNA Here G+C = 50% The G+C content is a genome structure

10. Life History Traits and Genome Structure Aerobiosis and G+C Content in Bacteria J.R. Lobry Université Claude Bernard - Lyon I CNRS UMR 5558 & INRIA Helix FRANCE

11. Aerobiosis and G+C Content in Bacteria AerobicAnaerobic Naya et al. (2002) J. Mol. Evol., 55:260

12. Aerobiosis and G+C Content in Bacteria AerobicAnaerobic Naya et al. (2002) J. Mol. Evol., 55:260 Why?

13. Metabolic cost of amino-acids in Aerobiosis Akashi & Gojobori (2002) PNAS, 99:3695 11.7 ATP 38.3 ATP 11.7 ATP 52.0 ATP 15.3 ATP 14.7 ATP 27.3 ATP

14. From amino-acid cost to Protein cost Akashi & Gojobori (2002) PNAS, 99:3695 Protein cost in ATP Protein concentration in cells

15. So what?

16. The growth of genomic data But available fossil DNA is < 0.00013 10 9 years...

17. All data are here

18. Dataset ~300 bacterial species ~1,000,000 proteins ~100,000,000 amino-acids

19. Akashi (2002) Naya (2002)

20. Interpretation Aerobic bacteria have a higher genomic G+C content than anerobic bacteria because this induces an average protein composition which is less expensive in aerobic conditions

21. Aerobiosis and G+C Content in Bacteria Life History Traits and Genome Structure J.R. Lobry Université Claude Bernard - Lyon I CNRS UMR 5558 & INRIA Helix FRANCE