de Mattos C C, de Mattos C A, Osburn B I, MacLachlan N J
Department of Veterinary Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis 95616.
Virology. 1994 May 15;201(1):173-7. doi: 10.1006/viro.1994.1281.
The genetic characteristics and phylogenetic relationships between the U.S. prototype strain of bluetongue virus serotype 10 (BTV 10), the modified live virus vaccine currently used in California, and three field isolates of BTV 10 obtained in 1980 and three in 1990 in California were determined by comparison of their L2 gene sequences. The L2 genes of the 1980 field isolates were very closely related to the L2 genes of the prototype strain and the vaccine strain, differing by only 0.1 to 0.5%. The 1990 field isolates diverged from all the other viruses by an average of 4.8%. They showed a high degree of genetic similarity that ranged from 98.2 to 99.7% and formed a separate group. All BTV 10 viruses derived from a common ancestor (bootstrap value 100%) from which two different lineages have diverged giving rise to two monophyletic groups, one including all the 1990 viruses and the other the prototype, the vaccine, and all 1980 field strains. The bootstrap analyses placed a 100% confidence value at each of these two nodes. These results indicate that two different lineages of BTV 10 circulated in California between 1953 and 1990. The effect of the vaccine on the evolutionary pathways of the BTV 10 population present in California in 1980 was not clearly established, but it did not influence the evolution of the BTV 10 field isolates obtained in 1990.
通过比较蓝舌病病毒血清型10（BTV 10）的美国原型毒株、加利福尼亚州目前使用的改良活病毒疫苗以及1980年在加利福尼亚州获得的3株BTV 10野外分离株和1990年的3株野外分离株的L2基因序列，确定了它们之间的遗传特征和系统发育关系。1980年野外分离株的L2基因与原型毒株和疫苗株的L2基因密切相关，差异仅为0.1%至0.5%。1990年的野外分离株与所有其他病毒平均有4.8%的差异。它们表现出高度的遗传相似性，范围在98.2%至99.7%之间，并形成一个单独的组。所有BTV 10病毒都来源于一个共同祖先（自展值为100%），从该祖先分化出两个不同的谱系，产生两个单系群，一个包括所有1990年的病毒，另一个包括原型毒株、疫苗株和所有1980年的野外毒株。自展分析在这两个节点的每一个都给出了100%的置信值。这些结果表明，1953年至1990年间，两种不同谱系的BTV 10在加利福尼亚州传播。疫苗对1980年加利福尼亚州存在的BTV 10种群进化途径的确切影响尚未明确，但它并未影响1990年获得的BTV 10野外分离株的进化。
