Figure 5.

Phylogenetic tree of intein splicing domains. This unrooted distance tree was constructed by the neighbour-joining method using PAUP*4b10 [52] with the default settings. Numbers on the branches indicate the percentages of bootstrap support derived from a heuristic search with 100 random addition replicates; this search included a tree-bisection-reconnection branch-swapping algorithm. All bootstrap values > 50 have been reported except in cases where allelic inteins fall within a well-supported (95–100% bootstrap) group, when some values >50 have been omitted for reasons of space. Inteins encoded by nuclear genes are highlighted with an asterisk. The alignment used is available as supplementary data (5).