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Prokaryote genome fluidity is dependent on effective population size.
Nadia Andrea Andreani1,2, Elze Hesse3, Michiel Vos2
1Department of Comparative Biomedicine and Food Science (BCA), University of Padova, Padua, Italy.
The ISME Journal
|April 1, 2017
Summary
Bacterial genome fluidity, the variation in accessory genes, is linked to higher genetic diversity within species. This suggests neutral evolution, not other factors, drives changes in prokaryotic genomes.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genomics
Background:
- Prokaryotic genomes are known for their fluidity, exhibiting significant variations in accessory gene content among strains.
- Mechanisms like gene loss, lateral gene transfer, and gene duplication contribute to this genomic plasticity.
- The evolutionary drivers behind prokaryotic genome fluidity remain incompletely understood.
Purpose of the Study:
- To systematically analyze and compare the degree of genome fluidity across different bacterial species.
- To investigate the relationship between genome fluidity and various evolutionary factors.
Main Methods:
- Systematic analysis of genome fluidity across bacterial species.
- Correlation analysis between genome fluidity and synonymous nucleotide diversity of the core genome (as a proxy for effective population size, Ne).
- Assessment of the influence of genome size, phylogeny, and homologous recombination rates.
Main Results:
- Genome fluidity was found to be positively correlated with synonymous nucleotide diversity of the core genome.
- No significant effects of genome size, phylogeny, or homologous recombination rate on genome fluidity were observed.
- The findings support a model where neutral evolution plays a substantial role in accessory gene content turnover.
Conclusions:
- Effective population size (Ne), indicated by synonymous nucleotide diversity, is a key factor associated with bacterial genome fluidity.
- Genome fluidity in prokaryotes appears to be largely shaped by neutral evolutionary processes rather than selection-driven factors like recombination rate or genome size.
- Accessory gene content turnover is predominantly influenced by neutral evolution, contributing to the observed genome fluidity in bacterial species.