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Measuring Microbial Mutation Rates with the Fluctuation Assay
Published on: November 28, 2019
Host-parasite coevolution and optimal mutation rates for semiconservative quasispecies
Yisroel Brumer1, Eugene I Shakhnovich
1Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Summary
This study models host-parasite coevolution with DNA replication, finding optimal mutation rates converge for hosts. Parasite mutation rates differ significantly from the optimum, explaining lower viral mutation rates.
Area of Science:
- Evolutionary biology
- Genetics
- Molecular biology
Background:
- Host-parasite coevolution is a key driver of evolutionary dynamics.
- DNA replication mechanisms, specifically semiconservative replication, can influence evolutionary trajectories.
- Previous models often simplified DNA replication as conservative.
Purpose of the Study:
- To extend host-parasite coevolution models by incorporating semiconservative DNA replication.
- To investigate the impact of semiconservative replication on optimal mutation rates for hosts and parasites.
- To reconcile theoretical predictions with experimental observations in coevolutionary systems.
Main Methods:
- Developed a theoretical model of host-parasite coevolution.
- Incorporated semiconservative DNA replication for both host and parasite genomes.
- Analyzed the effects of genome length and immune system interactions on optimal mutation rates.
Main Results:
- Optimal mutation rates for semiconservative and conservative hosts converge at realistic genome lengths.
- The conservative approximation for hosts is justified under certain conditions.
- While optimal mutation rates for semiconservative and conservative parasites are similar, their behavior away from the optimum differs significantly.
Conclusions:
- Semiconservative DNA replication in hosts does not drastically alter optimal mutation rates compared to conservative models for realistic genomes.
- Differences in off-optimum behaviors for semiconservative parasites are significant.
- The need for parasites to survive across diverse hosts may explain lower mutation rates in semiconservative viruses.
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