Phylogenetic analysis of the nucleotide sequences for the HN gene of 22 avian paramyxovirus type 2 viruses reveals marked heterogeneity.

The nucleotide sequence of the HN gene was determined for 21 isolates of avian paramyxovirus type 2 virus and compared with the published HN gene of APMV-2/chicken/California/Yucaipa/56. The HN gene of the 22 viruses had five different lengths in the range of 1737 to 1755 nucleotides coding for 579 to 585 amino acids. Phylogenetic analysis of a corresponding 1734-nucleotide sequence from the HN gene of each virus established five genetic groups (I to V), two of which (II and IV) could be divided into two sub-groups (IIa and IIb; and IVa and IVb). Although there were some exceptions, generally isolates placed in the same genetic group had >80% similarity in nucleotide sequence and <80% with the other isolates; while those in the same sub-group had >90% nucleotide sequence similarity.