Figure 5

Phylogenetic tree of noroviruses with and without the bovine sequences: The names and NCBI accession number are shown for each strain. The GI, GII and the murine sequence groups are indicated. The evolutionary units (eu) are the distances in terms of number of mutations. The tree that includes the bovine norovirus sequences is shown in black while changes in tree topology due to the exclusion of the bovine sequences are shown in red. Red slashes indicate the bovine branches AB, CD, CE and DF that get excluded in the tree constructed without the bovine sequences. Instead, branch C'E' connects the GI group to the GII group. Distances which undergo the maximum changes are enclosed within green boxes while the corresponding changed distances are enclosed within red boxes. All other distances remain nearly identical in both trees. The bigger green and the red boxes at the top left hand corner of the figure show calculations of the GI-bovine distance in one tree and the GI-GII distance in the other tree. The green square bracket indicates a cluster of GII sequences whose branch lengths are within the values shown. The sequences used in the trees are identical with those used in earlier analysis (Chakravarty et al., 2005). Both trees were drawn using the same neighbor-joining methods under identical distance models and sequence alignment parameters as described in the text.