Supplementary material for Murray *et al*. (August 7, 2001) *Proc. Natl. Acad. Sci. USA*, 10.1073/pnas.171178898

**Fig. 4.** Two-dimensional hierarchical clustering of the complete DNA/DNA hybridization data set. Pearson correlation coefficient and
complete linkage analysis were used to cluster the log normalized ratios test reference^{-1}). Black represents log ratios near 0, bright green represents ratios approaching 1.5, and dark red represents ratios approaching
0.30. Gray squares represent missing or insufficient data. Means of duplicate experiments are shown. Each column shows the
ratios for test bacterial strains, from left to right, as follows: (1) *E. coli*, (2) *S. woodyi*, (3) isolate PV4, (4) *S. oneidensis* MR-4, (5) *S. putrefaciens* strain 95, (6) isolate W3 18-1, (7) *Shewanella *sp. strain 184, (8) *S. baltica*, (9) *Shewanella *sp. CL256/73, (10) *S. oneidensis*, DLM7, and (11) *S. oneidensis* MR-1.