Data from: Cryptic ecology among host generalist Campylobacter jejuni in domestic animals

Homologous recombination between bacterial strains is theoretically capable of preventing the separation of daughter clusters, and producing cohesive clouds of genotypes in sequence space. However, numerous barriers to recombination are known. Barriers may be essential such as adaptive incompatibility, or ecological, which is associated with the opportunities for recombination in the natural habitat. Campylobacter jejuni is a gut colonizer of numerous animal species and a major human enteric pathogen. We demonstrate that the two major generalist lineages of C. jejuni do not show evidence of recombination with each other in nature, despite having a high degree of host niche overlap and recombining extensively with specialist lineages. However, transformation experiments show that the generalist lineages readily recombine with one another in vitro. This suggests ecological rather than essential barriers to recombination, caused by a cryptic niche structure within the hosts.

细菌菌株间的同源重组（Homologous recombination）理论上可阻止子代簇的分离，并在序列空间中形成连贯的基因型云。但目前已知存在多种重组障碍。此类障碍可分为两类：一类为必需性障碍，例如适应性不相容；另一类为生态性障碍，这类障碍与自然生境中重组发生的机会相关。空肠弯曲杆菌（Campylobacter jejuni）是多种动物的肠道定植菌，同时也是人类主要的肠道病原体。本研究证实，尽管空肠弯曲杆菌的两大泛宿主谱系宿主生态位重叠度极高，且二者均可与专宿主谱系发生广泛重组，但二者在自然环境中并未表现出彼此重组的迹象。然而体外转化实验结果显示，这两类泛宿主谱系之间可高效发生重组。这表明重组障碍并非必需性障碍，而是由宿主内部隐蔽的生态位结构所引发的生态性障碍。