title: The phylogeny of Turnip mosaic virus; comparisons of 38 genomic sequences reveal a Eurasian origin and a recent 'emergence' in east Asia.
abstract: The genomes of a representative world-wide collection of 32 Turnip mosaic virus (TuMV) isolates were sequenced and these, together with six previously reported sequences, were analysed. At least one-fifth of the sequences were recombinant. In phylogenetic analyses, using genomic sequences of Japanese yam mosaic virus as an outgroup, the TuMV sequences that did not show clear recombination formed a monophyletic group with four well-supported lineages. These groupings correlated with differences in pathogenicity and provenance; the sister group to all others was of Eurasian B-strain isolates from nonbrassicas, and probably represents the ancestral TuMV population, and the most recently 'emerged' branch of the population was probably that of the BR-strain isolates found only in east Asia. Eight isolates, all from east Asia, were clear recombinants, probably the progeny of recent recombination events, whereas a similar number, from other parts of the world, were seemingly older recombinants. This difference indicates that the presence of clear recombinants in a subpopulation may be a molecular signature of a recent 'emergence'.
authors.affiliation: Laboratory of Plant Virology, Faculty of Agriculture, Saga University, Saga 840-8502, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tomimura
authors.forename: A J
authors.initials: AJ
authors.lastname: Gibbs
authors.forename: C E
authors.initials: CE
authors.lastname: Jenner
authors.forename: J A
authors.initials: JA
authors.lastname: Walsh
authors.forename: K
authors.initials: K
authors.lastname: Ohshima
mesh_terms: D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D004587:Electrophoresis, Agar Gel; D019143:Evolution, Molecular; D016678:Genome; D005843:Geography; D008969:Molecular Sequence Data; D010802:Phylogeny; D017800:Potyvirus / Q000235:genetics*; D017422:Sequence Analysis, DNA