Simple Sequence Repeats in Escherichia coli: Abundance, Distribution, Composition, and Polymorphism

Table 1.

Numbers of Loci Exhibiting Simple Sequence Repeats of Given Structure in the Genome of E. coliStrain K12

No. of repeats per locus Motif length in nucleotides
mono- di- tri- tetra- penta- hexa-
 3 163,345 (163,134) 7,081 (9,538) 2,353* (778) 51 (52) 3 (0)
 4 42,901* (40,795) 465 (590) 64* (12) 1 (0)
 5 13,837* (10,262) 28 (39) 2 (0)
 6 4,123* (2,570) 1 (2)
 7 1,000* (625)
 8 217* (158)
 9 22 (39)
10 1 (11)
  • Genome-wide frequencies of SSR arrays of given motif length and repeat number were compared to mean frequencies in computer-generated randomized genomes (shown in parentheses). (*) Significant deviations from normal distribution-based expectations at the 0.001 level are indicated by asterisks.

This Article

  1. Genome Res. 10: 62-71

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