Phylogenetic positions of the endosymbionts of the lygaeoid bugs on the basis of groEL gene sequences. A consensus tree inferred by the Bayesian method with 39 sequences (MrBayes; 1,547 bp, 850 variable sites, 719 parsimony-informative sites, 10,000,000 generations, 10,000 trees, samplefreq = 1,000, burn in = 2,500) is shown. The tree has been rooted with Vibrio cholerae as an outgroup. Support values of greater than 0.5 are indicated at the nodes.