Figure 2. Neighbor-joining bootstrap tree (1,000 replicates, pairwise deletion comparisons, Tamura-Nei model) shows that morbillivirus fragments isolated from northern sea otters are identical to those of the 2002 PDV isolates. All known corresponding phosphoprotein gene fragments from morbilliviruses (Technical Appendix) were compared by using Molecular Evolutionary Genetics Analysis software version 3.1 (www.megasoftware.net/mega.html). Scale bar indicates number of nucleotide substitutions per site.