TABLE 1.
Comparison of nonsynonymous divergences among pairs of obligate insect endosymbionts and related free-living bacteria
| Genome paira | Phylum | Host | Genome wide |
Conserved core |
Estimated time since divergence (MY)e | ||
|---|---|---|---|---|---|---|---|
| n | Mean dN ± SD | n | Mean dN ± SD | ||||
| Blattabacterium (BPLAN-BGE) | Bacteroidetes | Blattaria (cockroaches) | 570 | 0.130 ± 0.073 | 125 | 0.113 ± 0.062 | 150-300 |
| “Ca. Sulcia” (DSEM-GWSS) | Bacteroidetes | Auchenorrhyncha (cicadas, leafhoppers, spittlebugs, etc.) | 202 | 0.141 ± 0.080 | 126b | 0.131 ± 0.075 | 200 |
| Flavobacterium johnsoniae-Flavobacterium psychrophilum | Bacteroidetes | Free living | 1,268 | 0.148 ± 0.075 | 119b,c | 0.097 ± 0.096 | NA |
| Bacteroides thetaiotaomicron-Bacteroides fragilis | Bacteroidetes | Free living | 1,962 | 0.115 ± 0.073 | 123b,d | 0.047 ± 0.043 | NA |
| “Ca. Blochmannia” (BPEN-BFL) | Proteobacteria | Camponotini (ants) | 577 | 0.225 ± 0.106 | 126b | 0.186 ± 0.088 | 16-20 |
| Buchnera (APS-SG) | Proteobacteria | Aphidoidea (aphids) | 458 | 0.149 ± 0.085 | 125 | 0.112 ± 0.066 | 50-70 |
| Buchnera (APS-BP) | Proteobacteria | Aphidoidea (aphids) | 458 | 0.315 ± 0.173 | 125 | 0.238 ± 0.130 | 150-200 |
| E. coli-Salmonella enterica | Proteobacteria | Free living | 2,940 | 0.067 ± 0.058 | 125 | 0.020 ± 0.023 | 100-150 |
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.