Evolution under fluctuating environments explains observed robustness in metabolic networks
| Autor: | Thomas Pfeiffer, Orkun S. Soyer |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
inorganic chemicals
QH301-705.5 Systems biology Cell Biology/Microbial Physiology and Metabolism Single gene Biology Environment Gene Deletions Models Biological complex mixtures Cellular and Molecular Neuroscience Computational Biology/Metabolic Networks QH301 Molecular evolution Genetics Computer Simulation Biomass Selection Genetic Biology (General) Molecular Biology QH426 Ecology Evolution Behavior and Systematics Computational Biology/Systems Biology Ecology Biochemistry/Theory and Simulation Human evolutionary genetics fungi Robustness (evolution) Computational Biology Gene deletion equipment and supplies Genetics and Genomics/Microbial Evolution and Genomics Biological Evolution Computational Biology/Evolutionary Modeling Biochemistry/Molecular Evolution Computational Theory and Mathematics Evolutionary Biology/Microbial Evolution and Genomics Modeling and Simulation Subfunctionalization bacteria Biological system Mathematics Gene Deletion Metabolic Networks and Pathways Research Article |
| Zdroj: | PLoS Computational Biology, Vol 6, Iss 8 (2010) PLoS Computational Biology |
| ISSN: | 1553-7358 |
| Popis: | A high level of robustness against gene deletion is observed in many organisms. However, it is still not clear which biochemical features underline this robustness and how these are acquired during evolution. One hypothesis, specific to metabolic networks, is that robustness emerges as a byproduct of selection for biomass production in different environments. To test this hypothesis we performed evolutionary simulations of metabolic networks under stable and fluctuating environments. We find that networks evolved under the latter scenario can better tolerate single gene deletion in specific environments. Such robustness is underlined by an increased number of independent fluxes and multifunctional enzymes in the evolved networks. Observed robustness in networks evolved under fluctuating environments was “apparent,” in the sense that it decreased significantly as we tested effects of gene deletions under all environments experienced during evolution. Furthermore, when we continued evolution of these networks under a stable environment, we found that any robustness they had acquired was completely lost. These findings provide evidence that evolution under fluctuating environments can account for the observed robustness in metabolic networks. Further, they suggest that organisms living under stable environments should display lower robustness in their metabolic networks, and that robustness should decrease upon switching to more stable environments. Author Summary One of the most surprising recent biological findings is the high level of tolerance organisms show towards loss of single genes. This observation suggests that there are certain features of biological systems that give them a high tolerance (i.e. robustness) towards gene loss. We still lack an exact understanding of what these features might be and how they could have been acquired during evolution. Here, we offer a possible answer for these questions in the context of metabolic networks. Using mathematical models capturing the structure and dynamics of metabolic networks, we simulate their evolution under stable and fluctuating environments (i.e., available metabolites). We find that the latter scenario leads to evolution of metabolic networks that display high robustness against gene loss. This robustness of in silico evolved networks is underlined by an increased number of multifunctional enzymes and independent paths leading from initial metabolites to biomass. These findings provide evidence that fluctuating environments can be a major evolutionary force leading to the emergence of robustness as a side effect. A direct prediction resulting from this study is that organisms living in stable and fluctuating environments should display differing levels of robustness against gene loss. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|