Rapid Pathway Evolution Facilitated by Horizontal Gene Transfers across Prokaryotic Lineages
Figure 2
Prokaryotic species analyzed and the phylogenetic tree, overlaid with rapid pathway acquisition events.
Species codes and taxonomic classifications are from the KEGG database [15] (for complete species names, see Table S1). Branch lengths reflect evolutionary time estimated by Ciccarelli et al. [14] to some extent, without impairing readability. Symbols on the tree indicate the places where pathways were acquired rapidly (see the main text). Small circles indicate a single appearance, whereas large symbols of the same shape and color indicate the independent acquisition of the same pathway at different places on the phylogenetic tree. Colors indicate the metabolic categories in which the pathway is involved; shapes have no special meaning.