Example of a query in the Strain Comparison Page for more than two strains. Top, the query page shows the 6 comparisons currently available (others will be added as new genome sequences are finished and released). Bottom, the result of a query performed for Escherichia coli strains O157:H7 Sakaï, O157:H7 EDL933, K12 and UPEC-CFT073 is summarized. In several loci, the size of the repeat is listed differently for the different strains, which is due to different detections by the Tandem Repeats Finder, usually as a result of internal variations within the tandem array. Total length is calculated from positions of matching flanking sequences in the different strains, and does not necessarily correspond to the length of the tandem repeat detected by TRF in the locus. "Number of alleles" refers to the number of predicted sizes differing by at least 5 bp among the strains compared.