Metzgar D, Thomas E, Davis C, Field D, Wills C
Department of Biology, MC0116, University of California at San Diego, La Jolla, CA 92093-0116, USA.
Mol Microbiol. 2001 Jan;39(1):183-90. doi: 10.1046/j.1365-2958.2001.02245.x.
We have demonstrated hypervariability of native short-motif repeats (microsatellites) in Escherichia coli. Twenty-five of the longest microsatellites in the E. coli genome were identified. These were analysed for length variability among 22 wild-type (non-mutator) isolates from the E. coli collection of reference (ECOR). Non-coding mononucleotide repeats are consistently polymorphic among these genetically diverse E. coli. Length differences in variable microsatellites allowed all E. coli strains examined to be uniquely differentiated. Phylogenetic analysis of the variable repeats shows ubiquitous homoplasy at the level of divergence represented by the sample set, suggesting that these markers are hypermutable and should prove valuable for the discrimination of closely related strains that are not otherwise genetically differentiable. Genomic analyses suggest that similar markers are also likely to be found in all other prokaryotes.
我们已经证明了大肠杆菌中天然短基序重复序列（微卫星）的高度变异性。在大肠杆菌基因组中鉴定出了25个最长的微卫星。对来自大肠杆菌参考菌株库（ECOR）的22株野生型（非突变体）分离株的这些微卫星进行了长度变异性分析。在这些基因多样的大肠杆菌中，非编码单核苷酸重复序列始终具有多态性。可变微卫星的长度差异使得所有检测的大肠杆菌菌株都能被独特区分。对可变重复序列的系统发育分析表明，在样本集所代表的分歧水平上存在普遍的同塑性，这表明这些标记是高度可变的，并且对于区分其他方面无法通过基因区分的密切相关菌株应该是有价值的。基因组分析表明，在所有其他原核生物中也可能发现类似的标记。
