Phylogeny of the BRSV G gene. Phylogeny showing the relationship among 31 selected nucleotide sequences based on a 472 nt part from nucleotide number 178 to 649 of the G gene of BRSV. The sequences from this study, labelled with “*”, originated from 10 different farms with outbreaks of respiratory disease in Norway between 2009 and 2011, and one isolate from an outbreak in 1976. Included are also representatives of the six genetic subgroups of BRSV and recent published Swedish and Danish strains. The genetic subgroups (I-VI) and the strain type of the Norwegian sequences (A or B) are indicated on the right. The strains are indicated by the isolate name with GenBank Accession numbers AF188585, AF188586, AF188588, AF188604, JN619431, JN619439, JN619446, L27802, M58307, Y08717, Y08718, U92098, U92102, U92103, U24714-U24716, U33539 and U57823. The GenBank accession numbers of the Norwegian strains are: KF501149-KF501155, KF501159, KF501160 and KF501170-KF501172. The bootstrap values are shown next to the branches. The trees are drawn to scale, with branch lengths measured in the number of substitutions per site.