Abstract: In order to explore the genetic mutations of the F gene and HN gene and the law of molecular epidemiology of Newcastle disease virus in China,nine influenza virus NDV were isolated from some poultry yards in China,the whole F and HN cDNA fragments of them were amplified by reverse transcription polymerase chain reaction,with primers specific to F gene and HN gene.After cloning and sequecing,gene sequences were analyzed on homology and heredity evolution.The sequence analysis showed 8 NDV isolates belonged to genotype Ⅶ,and 1 NDV isolates belonged to genotype Ⅱ.The F gene of NDV isolates had a 1662 bp open reading fragment (ORF) and the homology of the nucleotide of F gene is from 83.5% to 84.2%. The HN gene of NDV isolates had 1716 or 1734 bp.The glycosylation site of HN in virulent virus strains absence on 538 aa.The results revealed that Ⅶ genotype was the main genotype of NDV occurred in China now,variation of F gene and HN gene might be related to frequent vaccine selection pressure.

Key words: Newcastle disease virus (NDV); F gene; HN gene; sequence analysis; genotype