FIG. 2.

Phylogenetic trees of the nucleotide sequences of NDV strains from nt 329 to 582 (tree A) and 47 to 1708 (tree B) of the F gene. Zimbabwe/90 and strains from genotype V are listed in tree A. See details in references 21 and 22. Other strains and their accession numbers are listed in Tables 1 and 2. The boxed strain CA 1085/71 was selected from genotype V (Fig. 1) for analyses of tree A to determine the phylogenetic positions of the U.S. isolates.