Analyses of bipartition spectra for 12 genomes of marine picocyanobacteria. (a) Out of 2,037 bipartitions, 155 were found to be supported with 70% or higher bootstrap values. Percentage values indicate the proportion of gene families that support each consensus bipartition. Only nine consensus bipartitions were found with the Condense software. These bipartitions, represented by orange stars and numbered from 1 to 9, do not conflict with one another and can be combined in a single consensus tree that has the same topology as the tree of core proteins (Figure 4a) except for the position of Prochlorococcus sp. MIT9313. Some consensus bipartitions are supported by a low percentage of gene families. This is likely an effect of the rapid divergence between marine Synechococcus and Prochlorococcus leading to very small internal branches in phylogenetic trees. (b) Modified Lento plot for bipartitions with at least 70% bootstrap support. For each bipartition (numbered from 1 to 9), positive values on the y axis give the number of gene families that support the bipartition for a given bootstrap value (color coded). Negative values give the number of families that conflict with this bipartition. A given gene family can conflict with several bipartitions.
Dufresne et al. Genome Biology 2008 9:R90 doi:10.1186/gb-2008-9-5-r90