Evolutionary Role of Restriction/Modification Systems as Revealed by Comparative Genome Analysis

Table 1.

Analysis of the Avoidance of Palindromes and RS of Length 4 and 6 in Bacterial Genomes (Wilcoxon Tests)

Bacteria Length 4 Length 6
Palindromes RMS Palindromes RMS
bias O/E bias bias O/E bias
aepe 0 0.78 NA 0 0.92 NA
aqae 0.46 NA 0.63 NA
arfu 0.48 NA 0.53 NA
basu 0.41 - 0.58 -
bobu 0.52 NA 0 0.89 NA
caje 0.51 NA 0.66 NA
chpn 0.43 NA 0 1.06 NA
chtr 0.40 NA 0 1.12 NA
esco 0.44 4* 0.44
hain 0.19 - 0.30 -
hepy 0.45 0 0.46 NA
meja 0.47 0 0.78 NA
meth 0 1.05 0 0 0.88 NA
myge 0.57 NA 0.76 NA
myle 0 1.07 NA 0 0.88 NA
mypn 0 0.78 NA 0.72 NA
mytu 0 0.95 NA 0 0.90 NA
neme 0.40 2* 0.35 0
psae 0.46 NA 0.63
pyab 0 0.91 NA - 0.83 NA
pyho 0 0.93 NA 0 0.90 NA
ripr 0.54 NA 0.73 NA
sysp 0.62 5* 0.41 0
thma - 0.67 NA - 0.83 NA
trpa - 0.72 2* - 0.86 NA
urur - 0.70 NA 0 0.91 NA
  • Palindrome bias is the test that palindromes are more biased than the remaining words. O/E displays the ratio observed/expected of the mean rank of palindromes sorted by decreasing avoidance. RMS avoidance is the result of the Wilcoxon test that RS are more biased than the remained palindromes.

  • Abbreviations: NA, unknown RMS on the species; n*, rank of the sole RS known in the species for 4-palindromes (not enough elements for nonparametric statistics); —, underrepresentation (P-value <0.001); -, underrepresentation (P-value <0.05); 0, no bias. See Methods for species abbreviations.

This Article

  1. Genome Res. 11: 946-958

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