The enteric, pathogenic spirochaete Brachyspira pilosicoli colonizes and infects a variety of birds and mammals, including humans. However, there is a paucity of genomic data available for this organism. This study introduces 12 newly sequenced draft genome assemblies, boosting the cohort of examined isolates by fourfold and cataloguing the intraspecific genomic diversity of the organism more comprehensively. We used several in silico techniques to define a core genome of 1751 genes and qualitatively and quantitatively examined the intraspecific species boundary using phylogenetic analysis and average nucleotide identity, before contextualizing this diversity against other members of the genus Brachyspira . Our study revealed that an additional isolate that was unable to be species typed against any other Brachyspira lacked putative virulence factors present in all other isolates. Finally, we quantified that homologous recombination has as great an effect on the evolution of the core genome of the B. pilosicoli as random mutation (r/m=1.02). Comparative genomics has informed Brachyspira diversity, population structure, host specificity and virulence. The data presented here can be used to contribute to developing advanced screening methods, diagnostic assays and prophylactic vaccines against this zoonotic pathogen.

中文翻译：

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同源重组作为多毛短螺旋体多样性驱动因素的证据

肠道致病性螺旋体Brachyspira pilosicoli定殖并感染多种鸟类和哺乳动物，包括人类。然而，该生物体的基因组数据很少。这项研究引入了 12 个新测序的基因组草图，将检查的分离株队列增加了四倍，并更全面地对生物体的种内基因组多样性进行了编目。我们使用了几种计算机技术来定义 1751 个基因的核心基因组，并使用系统发育分析和平均核苷酸同一性定性和定量地检查种内物种边界，然后将这种多样性与Brachyspira 属的其他成员联系起来 . 我们的研究表明，无法对任何其他短螺旋体进行物种分型的额外分离株缺乏所有其他分离株中存在的假定毒力因子。最后，我们量化了同源重组对多毛短螺旋体核心基因组进化的影响与随机突变一样大（r / m = 1.02）。比较基因组学为短螺旋体的多样性、种群结构、宿主特异性和毒力提供了信息。此处提供的数据可用于开发针对这种人畜共患病病原体的先进筛选方法、诊断分析和预防性疫苗。