Transcript Life History Traits and Genome Structure: Aerobiosis and G

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
Aerobic versus Anaerobic
• You need the presence of O2 to live, you are
aerobic (obligate)
• You need the absence of O2 to live, you are
anaerobic (obligate)
• [...snip...]
Anaerobic and
Aerobic Species
Only Anaerobic
Species
Aerobic >> Anaerobic
• In aerobic conditions (with O2) the oxydation of
one molecule of glucose (respiration) yields 38
ATP (metabolic currency unit). Short generation
times.
• In anaerobic conditions (without O2) the
fermentation of one molecule of glucose yields 2
ATP (metabolic currency unit). Long generation
times.
The generation time is a life history trait
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
Bacteria in the Universal Tree of Life
EUCARYA
Oryza
Drosophila
Homo
Saccharomyces
Prorocentrum
Tetrahymena
Crithidia
Physarum
ARCHAEA
Halococcus
Halobacterium
Methanococcus
?
Methanobacterium
Desulfurococcus
Thermoproteus
EUBACTERIA
Escherichia
Pseudomonas
Thermus
Streptomyces
Anacystis
Bacillus
« BACTERIA »
Bacteria and
Eucarya
Only Bacteria
Bacterial Genomes:
Circular dsDNA
Here G+C = 50%
The G+C content is a genome structure
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
Aerobiosis and G+C Content in Bacteria
Anaerobic
Aerobic
Naya et al. (2002) J. Mol. Evol., 55:260
Aerobiosis and G+C Content in Bacteria
Anaerobic
Why?
Aerobic
Naya et al. (2002) J. Mol. Evol., 55:260
Metabolic cost of amino-acids in Aerobiosis
38.3 ATP
11.7 ATP
52.0 ATP
11.7 ATP
27.3 ATP
14.7 ATP
15.3 ATP
27.3 ATP
Akashi & Gojobori (2002) PNAS, 99:3695
Protein cost in ATP
From amino-acid cost to Protein cost
Protein concentration in cells
Akashi & Gojobori (2002) PNAS, 99:3695
So what?
The growth of genomic data
But available fossil DNA is < 0.00013 109 years...
All data are here
Dataset
• ~300 bacterial species
• ~1,000,000 proteins
• ~100,000,000 amino-acids
Akashi (2002)
Naya (2002)
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
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