RESUMO
We studied the evolution of the G gene in the new genotype ON1 of RSV detected from patients with acute respiratory infection in Japan. Phylogenetic analyses and the evolutionary timescale were obtained by the Bayesian MCMC method. We also analyzed p-distance and positive selection sites. A new genotype ON1 emerged around 2001. The evolution rate was rapid (3.57 × 10(-3) substitutions/site per year). The p-distance was short and no positive selection site was found in the present strains. These results suggested that a new genotype ON1 of RSV-A emerged approximately10 years ago and spread to some countries with a high evolution rate.
Assuntos
Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/genética , Vírus Sincicial Respiratório Humano/isolamento & purificação , Proteínas do Envelope Viral/genética , Sequência de Aminoácidos , Evolução Molecular , Genótipo , Humanos , Japão , Dados de Sequência Molecular , Filogenia , Vírus Sincicial Respiratório Humano/química , Vírus Sincicial Respiratório Humano/classificação , Alinhamento de Sequência , Proteínas do Envelope Viral/químicaRESUMO
We investigated the evolution of the C-terminal 3rd hypervariable region of G gene in the prevalent human respiratory syncytial virus (RSV) subgroups A (RSV-A) and B (RSV-B) in Japan in 2008-2011. Phylogenetic analysis and the evolutionary timescale was obtained by the Bayesian Markov Chain Monte Carlo method. All 38 RSV-A strains detected were classified into genotype NA1 and the 17 RSV-B strains detected belonged to genotypes BA and GB2. NA1 subdivided around 1998 in the present phylogenetic tree. Genotype BA subdivided around 1994. The evolutionary rates for RSV-A and RSV-B were estimated at 3.63×10⻳ and 4.56×10⻳ substitutions/site/year, respectively. The mean evolutionary rate of RSV-B was significantly faster than that of RSV-A during all seasons. The pairwise distance was relatively short (less than 0.06). In addition, some unique sites under positive selection were found. The results suggested that this region of the RSV strains rapidly evolved with some unique amino acid substitutions due to positive pressure.
Assuntos
Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/genética , Proteínas do Envelope Viral/genética , Pré-Escolar , Evolução Molecular , Feminino , Humanos , Lactente , Recém-Nascido , Japão/epidemiologia , Masculino , Modelos Estatísticos , Filogenia , Seleção Genética , Estatísticas não ParamétricasRESUMO
Detailed genetic analysis was carried out of the VP4/VP2 coding region in human rhinovirus species C (HRV-C) strains detected in patients with acute respiratory infection in Japan. Phylogenetic trees were constructed by the neighbour-joining (NJ) and maximum-likelihood (ML) methods. The NJ phylogenetic tree assigned 11 genotypes to the present strains, whilst the ML tree showed that the strains diversified sometime in the early 1870 s. Moreover, the pairwise distance among the present strains was relatively long, and the rate of molecular evolution of the coding region was rapid (3.07 × 10(-3) substitutions per site per year). The results suggest that the present HRV-C strains have a wide genetic divergence and a unique evolutionary timescale.