Zhang Wenjuan, Zhang Yuan, Zhong Yang
1School of Life Sciences, Fudan University, Shanghai, 200433 China.
2Shanghai Center for Bioinformation Technology, Shanghai, 201203 China.
Chin Sci Bull. 2006;51(18):2236-2242. doi: 10.1007/s11434-006-2118-9.
Nonsynonymous-synonymous substitution rate ratio ( / ) is an important measure for evaluating selective pressure based on the protein-coding sequences. Maximum likelihood (ML) method with codon-substitution models is a powerful statistic tool for detecting amino acid sites under positive selection and adaptive evolution. We analyzed the hepatitis C virus (HCV) envelope protein-coding sequences from 18 general geno/subtypes worldwide, and found 4 amino acid sites under positive selection. Since these sites are located in different immune epitopes, it is reasonable to anticipate that our study would have potential values in biomedicine. It also suggests that the ML method is an effective way to detect adaptive evolution in virus proteins with relatively high genetic diversity.
非同义替换率与同义替换率之比（ / ）是基于蛋白质编码序列评估选择压力的重要指标。采用密码子替换模型的最大似然（ML）方法是检测正选择和适应性进化下氨基酸位点的强大统计工具。我们分析了来自全球18种常见基因/亚型的丙型肝炎病毒（HCV）包膜蛋白编码序列，发现了4个处于正选择下的氨基酸位点。由于这些位点位于不同的免疫表位，我们有理由预期本研究在生物医学领域具有潜在价值。这也表明ML方法是检测具有相对较高遗传多样性的病毒蛋白适应性进化的有效方法。
