Abstract：The full-length genome of porcine reproductive and respiratory syndrome virus (PRRSV) NB/04 strain isolated from Zhejiang was sequenced and analyzed. The results showed that the complete genome of NB/04 strain is 15408 nucleotides(nt) long , including 28nt Ploy(A) tail. The entire genome of NB/04 strain contains about nine open reading frames(ORFs), with 189nt in the 5’UTR and 150nt in the 3’UTR. Comparative analysis with the genomic sequences of domestic and abroad North American isolates showed that it seemed to be more extensive in Nsp2 of nonstructural regions and ORF5 of structural coding regions. Especially, Nsp2 and ORF5 share 79.3%-96.4 and 86.1%-95.5%of deduced amino acid identity with domestic and abroad North American isolates, respectively. Phylogenetic analysis based on Nsp2 deduced amino acid sequence suggested that domestic PRRSV isolates could be divided into two big genetic subgroups, the NB/04 strain belongs to the same subgroup as BJ-4 , the others including Ch-1a strain belongs to the other subgroup, which indicated that PRRSV has evolved to different extents . These results would enrich the information data of PRRSV genome and provide a valuable basis for further studay of biological characteristics , heredity and mutation of PRRSV.
