TABLE 2.
Genetic characteristics of endosymbionts of plant sap-sucking insectsa
| Organism | Proteo- bacterial group | G+C content of DNA (mol%) | % Coding | G+C content of inter- genic spaces (mol%) | Recognizable −35, −10 region preceding rRNA genes | Inverted repeats following rRNA genes | 3′ end of 16S rDNA contains Shine-Dalgarno complement | Translational coupling the normc | Increased A+T content in poorly conserved regions |
|---|---|---|---|---|---|---|---|---|---|
| T. princeps | β | 57.1 | 81.6 | 57.4 | − | − | + | − | − |
| B. aphidicola | γ | 26.3 | 87.9 | 19.1b | + | + | + | − | ? |
| C. ruddii | γ | 19.9 | >99.9 | − | − | − | + | + |
a
Interpretations were based on analysis of sequence data.
b
Decreases of 4 to 9 mol% G+C were found in the intergenic spaces of the genomes of Rickettsia prowazekii, Chlamydia trachomatis, E. coli, Haemophilus influenzae, P. aeruginosa, N. meningitidis, Ralstonia solanacearum, and Clostridium acetobutylicum.
c
Suggested by the large number of gene pairs in which the initiation codon and the stop codon overlap (12).