Restriction Profiling of 23S Microheterogenic Ribosomal Repeats for Detection and Characterizing of E. coli and Their Clonal, Pathogenic, and Phylogroups

Figure 5

(a) Hypothesis of clonality in E. coli strains based on 23S rrn restriction profiling. The primordial soup of E. coli microbes would have been comprised of two clonal groups, types I and IV coexisting with each other but predominated by type I strains. Over the course of evolution on accumulating mutation as a means for variation, type I or type IV would have given rise to type III by addition (former) or deletion (latter) of recognition sequence. The second scenario could be a rare event because accumulation of two mutations in a conserved region would be difficult. Type II being the rarest would have been evolved in similar basis to type III. (b) Hypothesis of linking phylogroups, Hae III profiles, and clonal types in E. coli. This diagram illustrates the clonal groups of commensal E. coli strains having both A phylogroups (dominant) and B1 phylogroups each being type I profiles. Pathogenic counterparts showed dominancy in type III restriction pattern followed by type I pattern. With respect to phylogroups, pathovars were predominant in B2 and B1 followed by D and E groups.