title: Punctuated equilibrium and positive Darwinian evolution in vesicular stomatitis virus.
abstract: RNA viruses possess the potential for rapid evolution and serve as excellent models to test evolutionary theory. Molecular phylogenetic analysis of the P gene for a larger number of diverse natural isolates of vesicular stomatitis virus reveals no evidence for a molecular clock but instead shows a stepwise evolutionary pattern unlike that ever seen before. Each step out from the tree's ancestral root to terminal branch tips correlates not with time of virus isolation but with a south-to-north geographical progression from Panama to the United States. The grossly unequal rates of change within this single species imply an underlying mechanism at odds with the prevailing notion that neutral changes are the dominating feature of molecular evolution. This is also a demonstration of punctuated equilibrium at the molecular level.
authors.affiliation: Cell and Molecular Biology Program, University of Nevada, Reno 89557.
authors.forename: S T
authors.initials: ST
authors.lastname: Nichol
authors.forename: J E
authors.initials: JE
authors.lastname: Rowe
authors.forename: W M
authors.initials: WM
authors.lastname: Fitch
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D002489:Central America; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009656:North America; D010750:Phosphoproteins / Q000235:genetics; D010802:Phylogeny; D012641:Selection, Genetic; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D010750:Phosphoproteins; D014764:Viral Proteins; D015678:Viral Structural Proteins