Internal fragments from 7 housekeeping
genes, adk (adenylate kinase), fumC (fumarate hydratase),
gyrB (DNA gyrase), icd (isocitrate/isopropylmalate dehydrogenase),
mdh (malate dehydrogenase), purA (adenylosuccinate dehydrogenase),
and recA (ATP/GTP binding motif of recombinase A)