Bacterial genomes vary considerably in terms of size and gene content. The proportion of a genome composed of horizontally acquired DNA or mobile genetic elements also varies, but follows an ecological pattern with more mobile genetic element genes being found in facultative intracellular bacteria than those considered extracellular and both containing more than obligately intracellular bacteria.

中文翻译：

---

社论：ICE 和 Small。

细菌基因组在大小和基因含量方面差异很大。由水平获得的 DNA 或可移动遗传元件组成的基因组的比例也有所不同，但遵循生态模式，在兼性细胞内细菌中发现的可移动遗传元件基因比被认为是细胞外细菌的多，并且两者都包含更多的专性细胞内细菌。