title: Origin and evolution of LX4 genotype infectious bronchitis coronavirus in China.
abstract: We investigated the genomic characteristics of 110 LX4 genotype strains of infectious bronchitis viruses (IBVs) isolated between 1995 and 2005 in China. The genome of these IBVs varies in size from 27596bp to 27790bp. Most IBV strains have the typical genomic organization of other gamacoronaviruses, however, two strains lacked 3a and 5b genes as a result of a nucleotide change within the start codon in the 3a or 5b genes. Analysis of our 110 viruses revealed that recombination events may be responsible for the emergence of the LX4 genotype with different topologies. Most of these viruses disappeared (before mid-2005) because they were not "fit" to adaptation in chickens. Finally, those of the "fit" viruses (after mid-2005) continued to evolve and have become widespread and predominant in commercial poultry. In addition, few of these viruses experienced recombination with those of the vaccine strains at the 3' end of the genome.
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Mengying
authors.initials: M
authors.lastname: Gao
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Yuqiu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Qiuling
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Zongxi
authors.initials: Z
authors.lastname: Han
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Huixin
authors.initials: H
authors.lastname: Li
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Lingfeng
authors.initials: L
authors.lastname: Chen
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Shuling
authors.initials: S
authors.lastname: Liang
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
authors.forename: Yuhao
authors.initials: Y
authors.lastname: Shao
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China. Electronic address: swliu@hvri.ac.cn.
authors.forename: Shengwang
authors.initials: S
authors.lastname: Liu
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002681:China; D018387:Codon, Initiator / Q000235:genetics; D018352:Coronavirus Infections / Q000662:veterinary* / Q000821:virology; D005814:Genes, Viral / Q000235:genetics; D014644:Genetic Variation; D016679:Genome, Viral / Q000235:genetics*; D005838:Genotype; D001351:Infectious bronchitis virus / Q000145:classification* / Q000235:genetics; D009154:Mutation; D010802:Phylogeny; D011200:Poultry; D011201:Poultry Diseases / Q000821:virology*; D011995:Recombination, Genetic; D064370:Spike Glycoprotein, Coronavirus / Q000235:genetics
chemical_list: D018387:Codon, Initiator; D064370:Spike Glycoprotein, Coronavirus
keywords: Clade I; Clade II; Evolution; Infectious bronchitis virus (IBV); LX4 genotype (QX-like); Topology