Department of Epidemiology and Biostatistics, School of Public Health, Southeast University, Nanjing 210009, China.
Jiangsu Provincial Center for Disease Control and Prevention, Department of Acute Infectious Diseases, Nanjing 210009, China.
Viruses. 2021 Sep 30;13(10):1970. doi: 10.3390/v13101970.
Measles virus (MeV) genotype B3 is one globally significant circulating genotype. Here, we present a systematic description of long-term evolutionary characterizations of the MeV genotype B3's hemagglutinin (H) gene in the elimination era. Our results show that the B3 H gene can be divided into two main sub-genotypes, and the highest intra-genotypic diversity was observed in 2004. MeV genotype B3's H gene diverged in 1976; its overall nucleotide substitution rate is estimated to be 5.697 × 10 substitutions/site/year, and is slowing down. The amino acid substitution rate of genotype B3's H gene is also decreasing, and the mean effective population size has been in a downward trend since 2000. Selection pressure analysis only recognized a few sites under positive selection, and the number of positive selection sites is getting smaller. All of these observations may reveal that genotype B3's H gene is not under strong selection pressure, and is becoming increasingly conservative. MeV H-gene or whole-genome sequencing should be routine, so as to better elucidate the molecular epidemiology of MeV in the future.
麻疹病毒（MeV）基因型 B3 是一种具有全球重要意义的流行基因型。在这里，我们系统地描述了消除时代 MeV 基因型 B3 血凝素（H）基因的长期进化特征。我们的研究结果表明，B3 H 基因可分为两个主要的亚基因型，2004 年观察到最高的种内多样性。MeV 基因型 B3 的 H 基因于 1976 年发生分歧；其总体核苷酸取代率估计为 5.697×10 取代/位点/年，且正在放缓。B3 基因型 H 基因的氨基酸取代率也在下降，自 2000 年以来，有效种群数量呈下降趋势。选择压力分析仅识别出少数几个受到正选择的位点，且阳性选择位点的数量正在减少。所有这些观察结果可能表明，B3 基因型 H 基因不受强烈选择压力的影响，且正变得越来越保守。MeV H 基因或全基因组测序应该成为常规操作，以便将来更好地阐明 MeV 的分子流行病学。
