Polyunsaturated fatty acid synthesis: what will they think of next?

Polyunsaturated fatty acids have crucial roles in membrane biology and signaling processes in most living organisms. However, it is only recently that molecular genetic approaches have allowed detailed studies of the enzymes involved in their synthesis. New evidence has revealed a range of pathways in different organisms. These include a complex sequence for synthesis of docosahexaenoic acid (22:6) in mammals and a polyketide synthase pathway in marine microbes.