Fig. 3.

Phylogenetic tree of selected type I TSs from several domains of life. Isoprenyl diphosphate synthases (IDSs) are included as an outgroup. The first two or three letters of each TS name represent the taxonomy of sponge from which it originated. Enzymes with ● have been biochemically tested, while those with ○ have not been tested. The major sesquiterpene products of enzymes marked with ▲ were fully characterized (SI Appendix, Supplementary Note), whereas enzymes with ✢ produce a mixture of terpenes identified only by GC-MS (SI Appendix, Figs. S18, S19, and S35). Entries marked with only ● did not produce terpenes under our experimental conditions.