RESUMO
The goal of this study is to research the genetic characteristics and relationship between HN and P genes of NDV. The nucleotide sequence and deduced amino acid sequence were analyzed for the Hemagglutinin-neuramindase (HN) and Phosphoprotein (P) gene of twelve field isolates of Newcastle disease virus (NDV) during 1997-2005 in China. The HN and P gene sequences of fifteen NDV reference strains from GenBank were also used in this study. The molecular evolution distance of nucleotides and amino acids were calculated by MEGA 4.0 software, and analysis of variance and correlations were analyzed by SPSS11.0 software among different length sequences of the HN gene or P gene. The nucleotide and amino acids correlation of HN and P gene were analyzed respectively. The correlation of evolution distance and isolation year were also calculated. The results indicated that there were difference and good correlation of nucleotide and amino acid among different length sequences of the HN gene or P gene. These results revealed that the HN and P gene of NDV have the different response to selective pressure to adopt to landscape and closely relationship on heredity mutations. Nucleotide variations of HN and P gene have relationship with isolation year of strains.