Phylogenetic trees based on alignments of the homing endonuclease domains. Phylogenetic trees based on alignments of the whole homing endonuclease from:A. PRP8 full-length inteins. B. VMA inteins. Asterisks denote the VMA intein homing endonucleases known to be active . The trees were constructed by the neighbour-joining method using PAUP*  and each represents a consensus derived from 100 bootstrap replicates. The numbers indicate the percentage bootstrap support (only nodes with >50% support are shown). Accession numbers of the intein sequences are as in Figures 1 and 3 or can be obtained from InBase . S. dairenensis and S. castellii are now included in the newly described genus Naumovia; S. exiguus and S. unisporus are now included in the genus Kazachstania .