title: Tracing the genetic history of porcine reproductive and respiratory syndrome viruses derived from the complete ORF 5-7 sequences: a Bayesian coalescent approach.
abstract: To trace the genetic history of porcine reproductive and respiratory syndrome virus (PRRSV), we determined the complete sequences of ORFs 5 to 7 of four PRRSV isolates. These sequences were analyzed together with published sequences from 146 isolates from various parts of the world using a Bayesian coalescent approach as well as Bayesian inference and maximum-likelihood methods. All of the European-type (EU-type) viruses were classified into one of two groups or unclassified (4 isolates), while all North American-type (NA-type) viruses belonged to one of three major groups or were unclassified (5 isolates). Within each genotype, no apparent periodic and/or geographic influence on the evolution of PRRSVs was observed. The evolutionary rate of PRRSV isolates was estimated to be 1.55 × 10(-3) substitutions/site/year, and the time of the most recent common ancestor (TMRCA) was 491.2 years ago. Here, the TMRCA for the EU- and NA-type viruses was 58.7 and 62.6 years ago, respectively. A Bayesian skyline plot revealed that the viruses evolved at an almost constant population size until the late 1970s, when they experienced a population expansion that continued until the late 1980s. The population size then remained constant again until the early 2000s, when a rapid, sharp decline in the effective number of infections occurred.
authors: Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
authors: Sook Hee
authors: SH
authors: Yoon
authors: Hyekwon
authors: H
authors: Kim
authors: Bongkyun
authors: B
authors: Park
authors: Heebal
authors: H
authors: Kim
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D019143:Evolution, Molecular; D005838:Genotype; D008969:Molecular Sequence Data; D059645:Mutation Rate; D016366:Open Reading Frames; D058974:Phylogeography; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D013552:Swine
chemical_list: D012367:RNA, Viral