title: Molecular characterisation of virulence graded field isolates of myxoma virus.
abstract: BACKGROUND
  Myxoma virus (MV) has been endemic in Europe since shortly after its deliberate release in France in 1952. While the emergence of more resistant hosts and more transmissible and attenuated virus is well documented, there have been relatively few studies focused on the sequence changes incurred by the virus as it has adapted to its new host. In order to identify regions of variability within the MV genome to be used for phylogenetic studies and to try to investigate causes of MV strain attenuation we have molecularly characterised nine strains of MV isolated in Spain between the years 1992 and 1995 from wide ranging geographic locations and which had been previously graded for virulence by experimental infection of rabbits.
  
  
  RESULTS
  The findings reported here show the analysis of 16 genomic regions accounting for approximately 10% of the viral genomes. Of the 20 genes analysed 5 (M034L, M069L, M071L, M130R and M135R) were identical in all strains and 1 (M122R) contained only a single point mutation in an individual strain. Four genes (M002L/R, M009L, M036L and M017L) showed insertions or deletions that led to disruption of the ORFs.
  
  
  CONCLUSIONS
  The findings presented here provide valuable tools for strain differentiation and phylogenetic studies of MV isolates and some clues as to the reasons for virus attenuation in the field.
authors.affiliation: Instituto Universitario de Biotecnología de Asturias, Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus El Cristo, Universidad de Oviedo, 33006 Oviedo, España. daltonkevin@uniovi.es
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Dalton
authors.forename: Ines
authors.initials: I
authors.lastname: Nicieza
authors.forename: Aroa
authors.initials: A
authors.lastname: Baragaño
authors.forename: Jose Manuel Martín
authors.initials: JM
authors.lastname: Alonso
authors.forename: Francisco
authors.initials: F
authors.lastname: Parra
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005814:Genes, Viral; D054643:INDEL Mutation; D008969:Molecular Sequence Data; D009233:Myxoma virus / Q000737:chemistry* / Q000302:isolation & purification / Q000472:pathogenicity*; D017354:Point Mutation; D011110:Polymorphism, Genetic; D011213:Poxviridae Infections / Q000662:veterinary* / Q000821:virology; D011817:Rabbits; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013030:Spain; D014412:Tumor Virus Infections / Q000662:veterinary* / Q000821:virology; D014774:Virulence