Cryptic lineages of the genus Escherichia.

ABSTRACT: Extended multilocus sequence typing (MLST) analysis of atypical Escherichia isolates was used to identify five novel phylogenetic clades (CI to CV) among isolates from environmental, human, and animal sources. Analysis of individual housekeeping loci showed that E. coli and its sister clade, CI, remain largely indistinguishable and represent nascent evolutionary lineages. Conversely, clades of similar age (CIII and CIV) were found to be phylogenetically distinct. When all Escherichia lineages (named and unnamed) were evaluated, we found evidence that Escherichia fergusonii has evolved at an accelerated rate compared to E. coli, CI, CIII, CIV, and CV, suggesting that this species is younger than estimated by the molecular clock method. Although the five novel clades were phylogenetically di

SUBMITTER: Walk ST 

PROVIDER: S-EPMC2765150 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature