FIG. 7.

Phylogenetic trees constructed by the neighbor-joining method (23) from estimated distances between TrpE and TrpG sequences. Species designations: Ec, Escherichia coli; St, Salmonella typhimurium; Ps, B. aphidicola (Pemphigus spyrothecae); Tc, B. aphidicola (Tetraneura caerulescens; Sc, B. aphidicola (Schlechtendalia chinensis); Dn, B. aphidicola (Diuraphis noxia); Ap, B. aphidicola (Acyrthosiphon pisum); Sg, B. aphidicola (Shizaphis graminum); Rp, B. aphidicola (Rhopalosiphum padi); Rm, B. aphidicola (Rhopalosiphum maidis).