Neighbor-joining tree showing phylogenetic relationships among the king scallop ELO and a selection of alphaproteobacteria, betaproteobacteria, and gammaproteobacteria (highlighted in green, red, and blue, respectively) based on six housekeeping gene sequences, including those for DNA gyrase subunit B (gyrB) (A), recombinase A (recA) (B), 60-kDa chaperonin (groEL) (C), citrate synthase (gltA) (D), methionine-tRNA ligase (metG) (E), and phosphoenolpyruvate synthase (ppsA) (F). See Table 2 for more details on the selected bacterial species and the corresponding proteins.