Merlo Lauren M F, Sadowsky Michael J, Ferguson John A, Dean Antony M
University of Minnesota, Department of Ecology, Evolution, and Behavior, Saint Paul, MN, USA.
Gene. 2006 Jul 19;376(2):240-7. doi: 10.1016/j.gene.2006.04.002. Epub 2006 May 5.
A single nucleotide polymorphism between Escherichia coli strains K12 and B is known to alter the mechanism by which the arginine repressor regulates arginine biosynthesis, from a regulated system in E. coli K12 to a deregulated system in E. coli B. Laboratory experiments have demonstrated that the different regulatory strategies are selectively favored under different environmental conditions. In this study we analyzed 537 E. coli strains and show that the argR allele in E. coli B, which causes deregulation, is rare in isolates obtained from natural sources. Moreover, sequence analysis of 85 strains shows no evidence of selection at the arginine repressor locus. This illustrates that analysis of sequence data is insufficient to detect selection of uncommon alleles in rare environments.
已知大肠杆菌K12菌株和B菌株之间的一个单核苷酸多态性会改变精氨酸阻遏物调节精氨酸生物合成的机制，从大肠杆菌K12中的一个受调控系统转变为大肠杆菌B中的一个失控系统。实验室实验表明，不同的调控策略在不同的环境条件下受到选择性青睐。在本研究中，我们分析了537株大肠杆菌菌株，结果表明，导致失控的大肠杆菌B中的argR等位基因在从自然来源获得的分离株中很少见。此外，对85株菌株的序列分析表明，在精氨酸阻遏物基因座上没有选择的证据。这说明对序列数据的分析不足以检测在稀有环境中罕见等位基因的选择情况。
