title: Genome Hotspots for Nucleotide Substitutions and the Evolution of Influenza A (H1N1) Human Strains.
abstract: In recent years a number of studies have brought attention to the role of positive selection during the evolution of antigenic escape by influenza strains. Particularly, the identification of positively selected sites within antigenic domains of viral surface proteins has been used to suggest that the evolution of viral-host receptor binding specificity is driven by selection. Here we show that, following the 1918 outbreak, the antigenic sites of the hemagglutinin (HA) viral surface protein and the stalk region of neuraminidase became substitution hotspots. The hotspots show similar patterns of nucleotide substitution bias at synonymous and nonsynonymous sites. Such bias imposes directionality in amino acid replacements that can influence signals of selection at antigenic sites. Our results suggest that the high accumulation of substitutions within the antigenic sites of HA can explain not only cases of antigenic escape by antigenic drift but also lead to occasional episodes of viral extinction.
authors.affiliation: Department of Biology, University of Winnipeg, Winnipeg, Manitoba R3B 2G3, Canada a.civetta@uwinnipeg.ca.
authors.forename: Alberto
authors.initials: A
authors.lastname: Civetta
authors.affiliation: Department of Physics, University of Winnipeg, Winnipeg, Manitoba, Canada.
authors.forename: David Cecil Murphy
authors.initials: DC
authors.lastname: Ostapchuk
authors.affiliation: Department of Biology, University of Winnipeg, Winnipeg, Manitoba R3B 2G3, Canada Department of Biochemistry, Ebonyi State University, Abakaliki, Nigeria.
authors.forename: Basil
authors.initials: B
authors.lastname: Nwali
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001483:Base Sequence; D019143:Evolution, Molecular; D040961:Genetic Drift; D016679:Genome, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000737:chemistry / Q000235:genetics*; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology*; D009439:Neuraminidase / Q000737:chemistry / Q000235:genetics*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics*
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase
keywords: antigenic drift; extinction; influenza; selection; substitution hotspots