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Published on: January 22, 2018
The evolution of modularity in bacterial metabolic networks
Anat Kreimer1, Elhanan Borenstein, Uri Gophna
1School of Mathematical Science, Tel Aviv University, Tel Aviv 69978, Israel.
Summary
Metabolic network modularity in bacteria is shaped by network size, environmental factors like niche breadth, and horizontal gene transfer. Modularity generally decreased over evolutionary time, linked to specialization.
Area of Science:
- Microbial Metabolism
- Evolutionary Biology
- Systems Biology
Background:
- Metabolic network modularity is crucial for understanding bacterial adaptation and evolution.
- Previous studies have explored modularity in specific species, but a large-scale, cross-kingdom analysis is lacking.
Purpose of the Study:
- To comprehensively characterize metabolic network modularity across the bacterial tree of life.
- To identify key determinants of metabolic modularity and trace its evolutionary trajectory.
Main Methods:
- Systematic quantification of metabolic network modularity for over 300 bacterial species.
- Reconstruction of ancestral metabolic networks to infer evolutionary trends.
- Analysis of topological, environmental, and genetic factors influencing modularity.
Main Results:
- Network size, environmental niche breadth, and horizontal gene transfer significantly determine metabolic modularity.
- Endosymbionts and mammal-specific pathogens exhibit lower modularity compared to species with broader niches.
- Bacterial species alternating between distinct niches show higher modularity.
- A general trend of decreasing modularity from ancestral to descendant bacteria was observed.
Conclusions:
- Metabolic network modularity is a dynamic trait influenced by multiple factors.
- Niche specialization and the integration of peripheral metabolic pathways contribute to the observed decrease in modularity over bacterial evolution.
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