TABLE 1.

Comparison of nonsynonymous divergences among pairs of obligate insect endosymbionts and related free-living bacteria

Genome pairaPhylumHostGenome wideConserved coreEstimated time since divergence (MY)e
nMean dN ± SDnMean dN ± SD
Blattabacterium (BPLAN-BGE)BacteroidetesBlattaria (cockroaches)5700.130 ± 0.0731250.113 ± 0.062150-300
Ca. Sulcia” (DSEM-GWSS)BacteroidetesAuchenorrhyncha (cicadas, leafhoppers, spittlebugs, etc.)2020.141 ± 0.080126b0.131 ± 0.075200
Flavobacterium johnsoniae-Flavobacterium psychrophilumBacteroidetesFree living1,2680.148 ± 0.075119b,c0.097 ± 0.096NA
Bacteroides thetaiotaomicron-Bacteroides fragilisBacteroidetesFree living1,9620.115 ± 0.073123b,d0.047 ± 0.043NA
Ca. Blochmannia” (BPEN-BFL)ProteobacteriaCamponotini (ants)5770.225 ± 0.106126b0.186 ± 0.08816-20
Buchnera (APS-SG)ProteobacteriaAphidoidea (aphids)4580.149 ± 0.0851250.112 ± 0.06650-70
Buchnera (APS-BP)ProteobacteriaAphidoidea (aphids)4580.315 ± 0.1731250.238 ± 0.130150-200
E. coli-Salmonella entericaProteobacteriaFree living2,9400.067 ± 0.0581250.020 ± 0.023100-150
  • a Accession numbers for genomes used in this analysis can be found in the supplemental material.

  • b TrpD is not fused with TrpG.

  • c ThrABC, LeuABCD, and LysA are absent in F. psychrophilum, and TrpC is a split gene in F. johnsoniae and F. psychrophilum.

  • d DapD, SucA, and AceF are absent in B. thetaiotamoicron and B. fragilis.

  • e Dates are based on insect fossils except for that for E. coli-S. enterica. MY, million years; NA, not available.