Genomics Research Center (one of The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Harbin Medical University, Harbin, China.
Genomics. 2013 Oct;102(4):331-7. doi: 10.1016/j.ygeno.2013.07.014. Epub 2013 Aug 6.
The deadly human typhoid agent was initially classified as a species called Salmonella typhi but later reclassified as a serovar of Salmonella enterica together with other pathogenically diverse serovars. The dynamic changes of Salmonella taxonomy reflect the need to clarify the phylogenetic status of the Salmonella serovars: are they discrete lineages or variants of a genetic lineage? To answer this question, we compared S. typhi and other Salmonella serotypes. We found that the S. typhi and Salmonella typhimurium strains had over 90% and ca. 80%, respectively, of their genes identical; however, between S. typhi and S. typhimurium, this percentage dropped to 6%, suggesting the existence of genetic boundaries between them. We conclude that S. typhi and the other compared Salmonella serovars have developed into distinct lineages circumscribed by the genetic boundary. This concept and methods may be used to delineate other Salmonella serotypes, many of which are polyphyletic, needing differentiation.
人类伤寒致命病原体最初被归类为沙门氏菌属 Typhi 种，但后来与其他具有不同病原体的血清型一起重新归类为沙门氏菌属肠杆菌血清型。沙门氏菌分类的动态变化反映了需要阐明沙门氏菌血清型的系统发育地位：它们是离散的谱系还是遗传谱系的变体？为了回答这个问题，我们比较了伤寒沙门氏菌和其他沙门氏菌血清型。我们发现伤寒沙门氏菌和鼠伤寒沙门氏菌菌株分别有超过 90%和约 80%的基因相同；然而，在伤寒沙门氏菌和鼠伤寒沙门氏菌之间，这一比例下降到 6%，表明它们之间存在遗传界限。我们的结论是，伤寒沙门氏菌和其他比较的沙门氏菌血清型已经发展成为由遗传界限界定的不同谱系。这一概念和方法可用于划定其他沙门氏菌血清型，其中许多血清型是多系的，需要加以区分。
