FIG. 3.

Chladogram (unrooted evolutionary tree) of RelE homologues in prokaryotes. The tree was calculated by PILEUP in the Wisconsin GCG package version 8.1.0(a). The aligned sequences shown in Fig. 2 were used as input. The lengths of horizontal lines indicate relative evolutionary distances, whereas the lengths of the vertical bars are arbitrary. The gram-negative bacterial species are shown in blue, the gram-positive bacterial species are shown in red, and the archaeal species are shown in green. For clarity, the deep-branching organism Aquifex aeolicus was grouped with the gram-negative bacteria.