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Punctuated equilibrium and positive Darwinian evolution in vesicular stomatitis virus
S T Nichol1, J E Rowe, W M Fitch
1Cell and Molecular Biology Program, University of Nevada, Reno 89557.
Summary
RNA virus evolution, specifically vesicular stomatitis virus, shows a unique stepwise pattern. Geographical progression, not time, drives these evolutionary changes, challenging current molecular evolution theories.
Area of Science:
- * Molecular evolution
- * Virology
- * Phylogenetics
Background:
- * RNA viruses exhibit rapid evolution, making them suitable models for evolutionary studies.
- * The prevailing theory suggests neutral changes dominate molecular evolution.
- * Understanding viral evolution mechanisms is crucial for public health.
Purpose of the Study:
- * To investigate the evolutionary patterns of vesicular stomatitis virus (VSV).
- * To test the applicability of molecular clock models to VSV evolution.
- * To explore the driving forces behind VSV genetic changes.
Main Methods:
- * Molecular phylogenetic analysis of the P gene from diverse natural VSV isolates.
- * Comparison of genetic divergence with virus isolation dates and geographical origins.
- * Assessment of evolutionary rates and patterns.
Main Results:
- * VSV evolution did not follow a molecular clock model.
- * A distinct stepwise evolutionary pattern was observed.
- * Evolutionary steps correlated with a geographical progression from Panama to the United States, not isolation time.
Conclusions:
- * VSV evolution is characterized by punctuated equilibrium at the molecular level.
- * Geographical factors, rather than time, appear to be the primary drivers of VSV genetic change.
- * The findings challenge the notion that neutral changes are the dominant force in molecular evolution.