The endemic faunae of Lake Baikal: their general biochemistry and detailed lipid composition

Abstract

The biochemical composition of the important endemic faunal groups in Lake Baikal, Siberia, have been examined. The major biochemical components were determined and detailed analyses of the lipid fractions are presented. The lipids are characterized by high levels of long-chain ω3 polyunsaturated fatty acids in the glyceride-esters, the presence of large amounts of triglyceride in pelagic and bathy-pelagic species with a complete absence of wax esters, and a very simple sterol composition dominated almost exclusively by cholesterol. The results are discussed in relation to present knowledge concerning both marine and freshwater lipids and the possible origin and evolution of the Baikalian fauna. Present theories concerning the likely role of long-chain polyunsaturates and wax esters in lipids are considered in the light of these present results and a link is suggested between sterol diversity and type of evolution.