title: Phylogenetic relationships and differential selection pressures among genotypes of dengue-2 virus.
abstract: To elucidate the processes controlling the emergence and spread of dengue-2 virus (DEN-2) we examined the evolution of viral isolates sampled from both local (Viet Nam) and global populations. Our phylogenetic analysis, incorporating envelope (E) glycoprotein sequences from 147 isolates of DEN-2, provided a more complete picture of viral diversity, with a newly defined "Cosmopolitan" genotype having a near global distribution and two other genotypes restricted to Asia. By analyzing rates of synonymous and nonsynonymous substitution we determined that genotypes have experienced different selection pressures, with some evidence of positive selection in the Cosmopolitan genotype and one of the two Asian genotypes, but that the transition from sylvatic to human transmission was not accompanied by adaptive evolution of the E gene. Although there was no association between selection pressures acting on the E gene and proposed virulence differences among genotypes, some putatively selected amino acid sites have previously been implicated in changing viral pathogenicity, most notably E-390, and may also affect transmittability. These findings have implications for the future spread of DEN-2.
authors.affiliation: Department of Zoology, University of Oxford, United Kingdom.
authors.forename: S Susanna
authors.initials: SS
authors.lastname: Twiddy
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Farrar
authors.forename: Nguyen
authors.initials: N
authors.lastname: Vinh Chau
authors.forename: Bridget
authors.initials: B
authors.lastname: Wills
authors.forename: Ernest A
authors.initials: EA
authors.lastname: Gould
authors.forename: Tamara
authors.initials: T
authors.lastname: Gritsun
authors.forename: Graham
authors.initials: G
authors.lastname: Lloyd
authors.forename: Edward C
authors.initials: EC
authors.lastname: Holmes
mesh_terms: D000349:Africa; D000569:Americas; D001208:Asia; D001315:Australia; D003716:Dengue Virus / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D006801:Humans; D012641:Selection, Genetic; D014759:Viral Envelope Proteins / Q000235:genetics*
chemical_list: D014759:Viral Envelope Proteins