Long-chain polyunsaturated fatty acids (LC-PUFA) are fundamental components of animal biology, playing essential roles in membrane organisation, cell signalling, neural function and developmental processes. In vertebrates, the biosynthesis of LC-PUFA depends on a relatively conserved and often limited set of desaturase and elongase enzymes, rendering many species partially dependent on dietary sources. In contrast, numerous invertebrate lineages retain the capacity to synthesise polyunsaturated fatty acids (PUFA) de novo, supported by a more diverse and flexible enzymatic repertoire.
This seminar explores the molecular and evolutionary basis of LC-PUFA biosynthesis in invertebrates, using the marine annelid Platynereis dumerilii as a tractable model system. By combining functional characterisation of fatty acyl desaturases and elongases with phylogenetic analyses, the work reveals how invertebrate pathways differ from vertebrate counterparts in both organisation and metabolic potential. These differences include the presence of alternative desaturation steps, expanded enzyme families and lineage-specific innovations that enable efficient LC-PUFA production from C18 fatty acid precursors.
Beyond pathway architecture, the seminar integrates lipidomic analyses to illustrate how LC-PUFA biosynthesis is regulated in vivo and how membrane lipid composition responds to environmental variables such as temperature. Together, these findings highlight the biochemical versatility of invertebrate lipid metabolism and underscore the value of invertebrate models for understanding the evolution, regulation and physiological significance of LC-PUFA biosynthesis across animals.