Maps of a genome quartet with organisms from four different bacterial phyla: Escherichia coli (Gram negative), Deinococcus radiodurans (Deinococcales), Bacillus subtilis (Gram positive) and Treponema pallidum (spirochete). Tree topologies assigned to the vertices are depicted in New Hampshire tree format near the corresponding vertex of the triangle and they are equivalent to the unrooted tree topologies as depicted in Figure 2. The three numbers associated with each tree topology indicate how many QuartOPs fall into each of the three zones: "total", 90% and 99% respectively. For definition of zones see figure 2. A) Probabilities are calculated according to Strimmer and von Haeseler . There is no single topology that is supported by the majority of the QuartOPs and all three possible tree topologies are supported by roughly equal number of QuartOPs at the different probability levels. B) Probabilities are calculated with MrBayes program . C) Bootstrap support values are plotted. For this case the zones are "total", 70% and 90% support, respectively. Bootstrapping appears to provide a more conservative reliability estimate than the posterior probabilities used in cases A and B. Nevertheless, each tree topology is still supported by a roughly equal number of bootstrapped datasets.