1. 0.05 Riesia pediculicola, P-symbiont of human body louse Pediculus humanus [AB263101] AT 50.6% Riesia pediculicola, P-symbiont of human head louse Pediculus capitis [AB263105] AT 51.0% Riesia pediculischaeffi, P-symbiont of chimpanzee louse Pediculus schaeffi [EF110573] AT 50.3% Riesia phthiripubis, P-symbiont of human pubic louse Pthirus pubis [EF110574] AT 52.4% Arsenophonus nasoniae, S-symbiont of parasitoid wasp Nasonia vitripennis [AY264674] AT 45.9% Arsenophonus arthropodicus, S-symbiont of louse fly Pseudolynchia canariensis [DQ115536] AT 46.0% Hamiltonella defensa, S-symbiont of aphid Acyrthosiphon pisum [AF293616] AT 45.9% Regiella insecticola, S-symbiont of aphid Acyrthosiphon pisum [AF293618] AT 45.7% Symbiont of bovine louse Haematopinus eurysternus [DQ076661] AT 52.2% Symbiont of pig louse Haematopinus suis [DQ076662] AT 51.1% Symbiont of bore louse Haematopinus apri [DQ076665] AT 51.9% S-symbiont of psyllid Calophya schini [AF263560] AT 54.5% Symbiont of elephant louse Haematomyzus elephantis [DQ076663] AT 55.3% P-symbiont of macaque louse Pedicinus obtusus (Jigokudani) [AB478978] AT 53.5% Wigglesworthia glossinidia, P-symbiont of tsetse fly Glossina brevipalpis [NC_004344] AT 51.2% Blochmannia floridanus, P-symbiont of ant Camponotus floridanus [AY334381] AT 52.2% Baumannia cicadellinicola, P-symbiont of sharpshooter Homalodisca coagulata [AY676877] AT 51.6% P-symbiont of grain weevil Sitophilus oryzae [AF005235] AT 45.7% Sodalis glossinidius, S-symbiont of tsetse fly Glossina morsitans [AY861701] AT 45.5% P-symbiont of pigeon louse Columbicola columbae [AB303382] AT 45.7% Symbiont of louse fly Craterina melbae [EF174495] AT 44.4% Serratia marcescens [AF124042] AT 45.5% Serratia symbiotica, S-symbiont of aphid Acyrthosiphon pisum [M27040] AT 45.9% Escherichia coli [J01695] AT 45.6% Vibrio cholerae [X74694] AT 46.3% P-symbiont of macaque louse Pedicinus obtusus (Yakushima) [AB478979] AT 53.5% Ishikawaella capsulata, P-symbiont of plataspid stinkbug Megacopta punctatissima [AB240157] AT 50.7% Buchnera aphidicola, P-symbiont of aphid Acyrthosiphon pisum [M27039] AT 50.0% Buchnera aphidicola, P-symbiont of aphid Yamatocallis tokyoensis [AB064507] AT 52.1% Buchnera aphidicola, P-symbiont of aphid Geoica urticularia [AJ296751] AT 51.2% 99/88/100 99/100/100 94/100/96 95/96/100 */100/* 99/100/100 100/100/100 97/100/100 100/100/100 72/94/* 96/81/* 100/100/100 84/*/95 */98/* */*/80 100/ 100 FIG. 1. Molecular phylogenetic placement of the symbiont of P. obtusus on the basis of 16S rRNA gene sequences. A maximum- likelihood (ML) tree inferred from 593 unambiguously-aligned nucleotide sites is shown; Bayesian (BA) and neighbor-joining (NJ) analyses gave essentially the same results. Statistical support values higher than 70% are indicated at the nodes in the order of ML/BA/NJ. Asterisks indicate statistical support values lower than 70%. Sequence accession numbers are shown in brackets. AT contents of the sequences are also shown. The sequences from the symbionts of the primate, animal and bird lice are highlighted in boldface.