Studies on features and frequencies of recombination in bacterial evolution

为了阐明细菌重组事件的特征和频率，将两种密切相关的细菌菌株混合并在无菌土壤样品中孵育。长时间孵育后，将细胞回收到固体培养基上，并进行Illumina测序。通过开发和使用名为“ShortReadManager”的计算工具（该工具现在在http：//www.ige.tohoku.ac.jp/joho/gf/index.php上发布）分析Illumina测序读数，没有发现表明两个菌株之间重组的证据。另一方面，将16S核糖体RNA基因的突变DNA片段插入到土壤细菌的基因组中，其中存在5个rRNA基因拷贝。预期突变片段将被野生型拷贝替换。 通过定量PCR分析，我们发现了多基因家族协同进化的证据。

To clarify features and frequencies of bacterial recombinational events, two closely related bacterial strains were mixed and incubated in a sterile soil sample. After a long period of incubation cells were recovered on a solid medium, and subjected to illumina sequencing. The illumina sequencing reads were analyzed by developing and using a computational tool named 'ShortReadManager', which is now released at http://www.ige.tohoku.ac.jp/joho/gf/index.php, and I found no evidence that indicates recombination between the two strains.On the other hand, mutated DNA fragment of 16S ribosomal RNA gene was inserted into a genome of a soil bacteria, in which 5 copies of rRNA gene are present. The mutated fragment was expected to be replaced by the wild-type copy. By quantitative PCR analysis, we found a evidence that suggests concerted evolution of multi gene family.