The Mutational Spectra of Microsatellite Repeats in Bacteria
| Organism | Repeat motif | Repeat length | N | Source | Number of mutations, by change in repeat number | Average change in allele length (in repeats) | Sign testp-value (insertions vs. deletions) | ||||||||
| deletions | insertions | ||||||||||||||
| −>2 | −2 | −1 | +1 | +2 | +>2 | ||||||||||
| H. influenzae | AGTC | 17 | 19 | (a) | 1[ii] | 3 | 11 | 3 | 1 | 0 | −.89 | ||||
| H. influenzae | AGTC | 23 | 14 | (a) | 0 | 0 | 9 | 4 | 1 | 0 | −.29 | ||||
| H. influenzae | AGTC | 32 | 22 | (a) | 0 | 1 | 12 | 9 | 0 | 0 | −.23 | ||||
| H. influenzae | AGTC | 38 | 8 | (a) | 1[ii] | 0 | 4 | 2 | 1 | 0 | −.63 | ||||
| (total from above) | AGTC | 17–38 | 63 | (a) | 2[ii] | 4 | 36 | 18 | 3 | 0 | −0.44 | p < .02 | |||
| E. coli | AC | 51 | 21 | (b) | 5 | 4 | 10 | 1 | 0 | 1 | −2.9 | p < .001 | |||
| M. gallisepticum | GAA | 12 | 44 | this work | 2 | 14 | 16 | 7 | 5 | 0 | −0.80 | p < .005 | |||
[i] N is the number of independent mutants analyzed. Repeat length refers to the number of repeats in the microsatellite before mutations have occurred. Length changes are shown in numbers of repeat motifs (a change of −2 in the AC repeat means that the sequence ACAC was deleted). For calculation of average change in length, these were conservatively counted as a loss of 4 repeats (since a loss of three repeats would not be seen in this system). Sign tests were not performed independently for each length of the H. influenzaemicrosatellite because of the small sample number. Data sources are as follows: (a) De Bolle et al. 2000; (b) Morel et al. 1998.
[ii] The actual magnitude of these mutations was not reported.