长期进化Streptococcus mitis和Streptococcus pneumoniae导致更高的遗传多样性,而不是在人类群体之间
Charlotte Davison1, Sam Tallman1, Megan de Ste-Croix1
1Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.
PLoS genetics
|June 6, 2024
概括
人类的细菌共生体,如Streptococcus mitis和Streptococcus pneumoniae,在人群内表现出更多的遗传多样性,而不是在人群之间. 较大的祖先有效种群大小 (Ne) 解释了这种模式,表明它.
科学领域:
- 微生物学 微生物学
- 进化生物学 进化生物学
- 基因组学就是基因组学.
背景情况:
- 了解人类细菌共生基因多样性是它们进化潜力的关键.
- 主体-细菌的基因组多样性相关性是有争议的,特别是关于地理结构.
- 菌株和肺炎菌株的种类为研究共生性到致病性提供了一个模型.
研究的目的:
- 研究Streptococcus mitis和Streptococcus pneumoniae的基因组多样性和演变.
- 为了比较这两种物种在人类群体内和人类群体之间的遗传变异.
- 确定驱动观察到的多样性模式的因素,例如祖先的种群规模.
主要方法:
- 对119个S. mitis和810个S. pneumoniae分离物的全基因组分析.
- 使用现场频谱统计数据分析同义和非同义变化的分析.
- 估计贝叶斯计算 (ABC) 建模以推断人口参数.
主要成果:
- 与S. pneumoniae相比,S. mitis在宿主内部和宿主之间表现出更高的遗传变异.
- S. mitis 拥有比 S. pneumoniae 更大的祖先有效种群大小 (Ne).
- 这两种物种在欧洲,东亚和非洲人群中都显示出有限的遗传差异化.
结论:
- 在S. mitis中,更高的祖先Ne保持了接近突变漂移平衡的变异.
- 肺炎已经从一个较小的祖先群体扩大.
- 大Ne,而不是高迁移,可能解释了两种物种有限的种群差异化,这是人类微生物组的共同特征.
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