title: Characteristics of influenza virus genome mutations.
abstract: Although the viral factors of host adaptation from domestic poultry to humans have been  studied several times since the first cases of direct transmission of highly pathogenic avian influenza  viruses from domestic poultry to humans were confirmed in 1997, the host-specific adaptation mechanisms  from waterfowl to domestic poultry remain unknown.  To study the mechanisms involved, a waterfowl-derived  virus was passaged in a chicken fibroblast cell line.  This passaged virus was found to have much higher  growth titer than that of the original virus and several mutations were discovered in its genome.  One of  the most characteristics was an increase of the polymorphism of the internal genes.  In addition, the general  applicability of this property to the field isolates of influenza A viruses by database sequences analysis  was confirmed, with the smallest amount of amino acid polymorphism in viral internal proteins observed in  waterfowl-derived viruses, more in domestic poultry and the most in human-derived viruses. Although specific  amino acid changes conserved in human-derived viruses were found, such amino acid changes were not observed  in poultry-derived viruses.
authors.affiliation: Division of Zoonosis, Department of Microbiology and Infectious Diseases,  Graduate School of Medicine, Kobe University, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Motoko
authors.initials: M
authors.lastname: Tanaka
authors.forename: Kyoko
authors.initials: K
authors.lastname: Tsumura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Ito
authors.forename: Etsuro
authors.initials: E
authors.lastname: Ono
authors.forename: Akiko
authors.initials: A
authors.lastname: Makino
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawaoka
authors.forename: Kyoko
authors.initials: K
authors.lastname: Shinya
mesh_terms: D000818:Animals; D002642:Chick Embryo; D004285:Dogs; D004372:Ducks / Q000821:virology; D016679:Genome, Viral; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics*; D061985:Madin Darby Canine Kidney Cells; D009154:Mutation; D017423:Sequence Analysis, RNA