A precise reconstruction of the emergence and constrained radiations of Escherichia coli O157 portrayed by backbone concatenomic analysis
A precise reconstruction of the emergence and constrained radiations of Escherichia coli O157 portrayed by backbone concatenomic analysis
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DOI：
10.1073/pnas.0812949106
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发表时间：
2009-05-26
影响因子：
11.1
通讯作者：
Tarr, Phillip I.
中科院分区：
文献类型：
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作者：
Leopold, Shana R.;Magrini, Vincent;Tarr, Phillip I.
稳定基因组区域的单核苷酸多态性（SNPs）提供了物种进化的持久测量。我们系统地鉴定了7个新测序或先前测序的具有进化指导意义的致病性大肠杆菌O157:H7、O157:H-和O55:H7的所有骨干orf序列中的每个SNP。1113个同义snp表明，这种病原体的最大集群仅在上个千年出现。出乎意料的是，在有限的生物集群中共享的snp表明，致病性O157: H7的生存受到严重限制，有效种群规模有限，这些生物在自然界中的生存非常脆弱，源库进化动力学，或者可能是具有选择优势的有限数量的突变。横跨rfb-gnd基因簇的单个大片段是O157从O55产生时唯一令人信服的重组骨干区域。这种串联基因组分析也支持使用snp来区分密切相关的病原体，用于感染控制和法医目的。然而，受限的辐射增加了在分离株之间建立错误联系的可能性。
Single nucleotide polymorphisms (SNPs) in stable genome regions provide durable measurements of species evolution. We systematically identified each SNP in concatenations of all backbone ORFs in 7 newly or previously sequenced evolutionarily instructive pathogenic Escherichia coli O157:H7, O157:H-, and O55:H7. The 1,113 synonymous SNPs demonstrate emergence of the largest cluster of this pathogen only in the last millennium. Unexpectedly, shared SNPs within circumscribed clusters of organisms suggest severely restricted survival and limited effective population sizes of pathogenic O157: H7, tenuous survival of these organisms in nature, source-sink evolutionary dynamics, or, possibly, a limited number of mutations that confer selective advantage. A single large segment spanning the rfb-gnd gene cluster is the only backbone region convincingly acquired by recombination as O157 emerged from O55. This concatenomic analysis also supports using SNPs to differentiate closely related pathogens for infection control and forensic purposes. However, constrained radiations raise the possibility of making false associations between isolates.