高致病性PRRSV ORF6和ORF7基因的遗传变异分析

Genetic Variance Analysis of Highly Pathogenic PRRSV ORF6 and ORF7 Genes

从GenBank中选取8株国内报道的高致病性猪繁殖与呼吸综合征病毒株,应用DNAStar软件对其ORF6、ORF7基因序列进行分析,与VR-2332株、LV株、国内及周边国家分离株进行核苷酸和推导氨基酸同源性比较,并绘制系统进化树.结果表明,高致病性猪繁殖与呼吸综合征病毒株的ORF6、ORF7核苷酸与VR-2332株的同源性为95.1%-95.4%、93.8%-94.1%,与欧洲型（LV）的同源性为69.4%-69.6%、67.9%-68.5%;ORF6、ORF7推导氨基酸与VR-2332株的同源性为97.7%、94.4%-95.2%,与欧洲型（LV）的同源性为80.0%-80.6%、65.3%-66.1%.系统进化树表明,8株高致病性猪繁殖与呼吸综合征病毒株仍属于美洲型.说明猪繁殖与呼吸综合征病毒不断变异的现今,ORF6和ORF7基因依然高度保守.

According to the sequences of eight highly pathogenic porcine reproductive and respiratory syndrome virus isolated from China and published in the Genbank.The ORF6 and ORF7 gene sequences were analysed using DNAStar and compared with those of VR-2332,LV and other strains isolated from China and circumjacent Country.The phylogenetic tree and the genetic variance of ORF6 and ORF7 gene sequence were analysed.The results showed that the homologous of ORF6,ORF7 Nuclear acid was 95.1%～95.4%、93.8%～94.1% with VR-2332 and 69.4 %～69.6%、67.9 %～68.5% with European（LV） viruses,The homologous of ORF6,ORF7 deduced amino acid was 97.7%、94.4%～95.2% with VR-2332 and 80.0 %～80.6%、65.3 %～66.1% with European（LV） viruses.The phylogenetic trees revealed eight highly pathogenic porcine reproductive and respiratory syndrome virus strains belong to American genotype.It indicated that the ORF6 and ORF7 of PRRSV still were conservative,even PRRSV is unceasing variance.