Figure 1.
Gains and losses of operons in Caenorhabditis nematodes. The numbers of C. elegans operons showing various presence/absence phylogenetic distributions are given at the top of the figure, with the inferred numbers of operon gains (circled) and losses presented on tree branches. There are no C. elegans operons that are absent in all of the other three Caenorhabditis species, but present in one or two of the outgroups (P. pacificus and B. malayi). A pair of linked black circles shows the presence of an operon, while a pair of unlinked white circles shows the absence of the operon. Dashes show undetermined status.
