title: Extended phylogeny of the equine arteritis virus sequences including South American sequences.
abstract: OBJECTIVE
  To perform genetic analysis of the ORF5 of equine arteritis virus (EAV) may provide new insights into the genetic evolution and origin of the Argentinean EAV sequences.
  
  
  METHODS
  A total of 76 sequences were analyzed by neighbor joining (NJ), maximum parsimony and maximum likelihood algorithms. The analysis of the selective pressures was performed using the Tajima's test.
  
  
  RESULTS
  The trees showed similar topologies. Two clades were identified: the first clade was formed by strains isolated mainly from a donkey, whereas the second clade presented four large groups from different geographic regions exclusively from Equus caballus. In this clade, we identified a group formed by South African and another one by South American and European sequences. In the latter, the monophyletic group was formed by seven Argentinean sequences. In the NJ tree, we identified a group formed by six Argentinean sequences. The Tajima's test showed a D value of 1.73663, indicating that the sequences analyzed follow a neutral evolution model.
  
  
  CONCLUSIONS
  We concluded that the Argentinean sequences have a paraphyletic origin and that the fixation of point mutation might follow the neutral model evolution; however, we identified purifying pressures that may be involved in the differentiation of the EAV sequences.
authors.affiliation: Virology, Faculty of Veterinary Sciences, National University of La Plata, La Plata, Argentina.
authors.forename: Germán Ernesto
authors.initials: GE
authors.lastname: Metz
authors.forename: Giselle Paula Martín
authors.initials: GP
authors.lastname: Ocampos
authors.forename: María Soledad
authors.initials: MS
authors.lastname: Serena
authors.forename: Sabrina Eliana
authors.initials: SE
authors.lastname: Gambaro
authors.forename: Edgardo
authors.initials: E
authors.lastname: Nosetto
authors.forename: María Gabriela
authors.initials: MG
authors.lastname: Echeverría
mesh_terms: D000465:Algorithms; D000818:Animals; D001118:Argentina; D018174:Arterivirus Infections / Q000662:veterinary* / Q000821:virology; D001483:Base Sequence; D007240:Equartevirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D005060:Europe; D019143:Evolution, Molecular; D014644:Genetic Variation; D006734:Horse Diseases / Q000821:virology*; D006736:Horses / Q000821:virology; D008297:Male; D008969:Molecular Sequence Data; D009656:North America; D010802:Phylogeny; D012661:Semen / Q000821:virology; D016415:Sequence Alignment / Q000662:veterinary; D013019:South Africa