Studies on features and frequencies of recombination in bacterial evolution

为了弄清细菌重组事件的特征和频率，将两个密切相关的细菌菌株混合并在无菌土壤样本中培养。经过长时间的孵育后，在固体培养基上回收细胞，并进行Illumina测序。通过开发和使用http://www.ige.tohoku.ac.jp/joho/gf/index.php，上发布的名为ShortReadManager的计算工具对Illumina测序读数进行分析，没有发现两个菌株之间存在重组的证据。另一方面，将16S核糖体RNA基因突变的DNA片段插入到土壤细菌的基因组中，其中存在5个拷贝的rRNA基因。突变的片段有望被野生型拷贝所取代。通过定量聚合酶链式反应分析，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.