Chemical defense and evolutionary trends in biosynthetic capacity among dorid nudibranchs (Mollusca: Gastropoda: Opisthobranchia)

摘要: An evolutionary scenario incorporating recent advances in phylogenetic research begins with an opisthobranch-pulmonate common ancestor that was herbivorous and had some diet-derived chemical defense. The Nudibranchia their closest relatives, the Notaspidea, form a lineage ancestors of which switched to feeding upon sponges deriving protection from metabolites contained them. Subsequently there have been repeated shifts food defensive metabolites, trends are evident ability detoxify, sequester utilize food, as well synthesize compounds de novo. Notaspidea display minor adaptive radiation foreshadows more extensive one various lineages nudibranchs. This review emphasizes changes occurred within Holohepatica, or dorid nudibranchs (order Doridacea). Their sister-group, Cladohepatica, consists three other orders, Dendronotacea, Arminacea, Aeolidiacea, has shift Cnidaria food. Dendronotacea often feed Octocorallia, combine spicules, defense, stinging capsules thereby suggest transition on sponges. A previous diet Octocorallia is suggested by use prostaglandins dendronotacean Tethys fimbria, eats crustaceans. bryozoans Arminacea accompanied different metabolites. Dorid evidently began sponge-feeders, but shifted variety organisms, others specialized kind they how do it. There (Ectoprocta) ascidians (Chordata: Urochordata) track rather than taxonomy crude correlation between genealogy sponge-feeding dorids. De novo synthesis documented this order appropriately positioned so effect. hypothesis capacity for acquired gene transfer across rejected, partly basis chirality organisms. Instead it proposed preadaptive phase followed evolution retrosynthetic mode, selection favoring enzymes enhance yield end products already present