FIG. 3.

Phylogenetic tree (16S rRNA gene sequences; maximum-likelihood method) showing the evolutionary relationship of the hepatopancreatic symbionts of P. scaber (boldface type) to selected species belonging to the main phylogenetic clades of the Mollicutes (indicated by vertical lines). The tree was rooted by using E. coli and Clostridium perfringens as outgroups. Nodes with bootstrap values (DNAPARS; 1,000 replicates) of >99% (•) and >50% (○) are marked. All marked nodes were observed in all other phylogenetic analyses in which maximum-parsimony and neighbor-joining algorithms were used (data not shown). Bar = 10 substitutions per 100 nucleotides.