Extended phylogeny of the equine arteritis virus sequences including South American sequences.
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.
Metz
Germán Ernesto
GE
Virology, Faculty of Veterinary Sciences, National University of La Plata, La Plata, Argentina.
Ocampos
Giselle Paula Martín
GP
Serena
María Soledad
MS
Gambaro
Sabrina Eliana
SE
Nosetto
Edgardo
E
Echeverría
María Gabriela
MG
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