Rates of molecular evolution are known to vary between species and across all kingdoms of life. Here, we explore variation in the rate at which bacteria accumulate mutations (accumulation rates) in their natural environments over short periods of time. We have compiled estimates of the accumulation rate for over 34 species of bacteria, the majority of which are pathogens evolving either within an individual host or during outbreaks. Across species, we find that accumulation rates vary by over 3700-fold. We investigate whether accumulation rates are associated to a number potential correlates including genome size, GC content, measures of the natural selection and the time frame over which the accumulation rates were estimated. After controlling for phylogenetic non-independence, we find that the accumulation rate is not significantly correlated to any factor. Furthermore, contrary to previous results, we find that it is not impacted by the time frame of which the estimate was made. However, our study, with only 34 species, is likely to lack power to detect anything but large effects. We suggest that much of the rate variation may be explained by differences between species in the generation time in the wild.

中文翻译：

---

调查细菌的进化速率变化。

已知分子进化的速率在物种之间以及整个生命王国中都不同。在这里，我们探索细菌在自然环境中短时间内累积突变的速率（累积速率）的变化。我们已经对超过34种细菌的积累速率进行了估算，其中大多数细菌是在单个宿主内或在暴发期间进化的病原体。在整个物种中，我们发现累积速率相差3700倍以上。我们调查累积速率是否与许多潜在的相关因素相关，包括基因组大小，GC含量，自然选择的度量以及估计累积速率的时间范围。在控制了系统发生非独立性之后，我们发现累积速率与任何因素均不显着相关。此外，与以前的结果相反，我们发现它不受估计时间范围的影响。但是，我们的研究只有34种，很可能没有能力检测到除大型影响之外的任何东西。我们建议，大部分速率变化可能是由于野生环境中世代时间上物种之间的差异造成的。