Functional Desaturase Fads1 (Δ5) and Fads2 (Δ6) Orthologues Evolved before the Origin of Jawed Vertebrates

摘要: Long-chain polyunsaturated fatty acids (LC-PUFAs) such as arachidonic (ARA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) are essential components of biomembranes, particularly in neural tissues. Endogenous synthesis ARA, EPA DHA occurs from precursor dietary linoleic α-linolenic acid through elongation Δ5 Δ6 desaturations. With respect to desaturation activities some noteworthy differences have been noted vertebrate classes. In mammals, the activity is allocated Fads1 gene, while Fads2 a desaturase. contrast, teleosts show distinct combinations desaturase (e.g. bifunctional or separate desaturases) apparently Fads2-type genes. To determine timing Fads1-Δ5 Fads2-Δ6 evolution vertebrates we used combination comparative functional genomics with analysis key phylogenetic species. Our data that genes respectively, evolved before gnathostome radiation, since catshark Scyliorhinus canicula has orthologues both gene families. Consequently, loss secondary episode, existence same group most likely occurred independent mutations into type Unexpectedly, also establish events expansion taken place birds reptiles. Finally, fourth Fads (Fads4) was found an exclusive occurrence mammalian genomes. findings enlighten history crucially important family metabolism physiology provide explanation how observed lineage-specific duplications, losses diversifications might be linked habitat-specific food web structures different environments over geological timescales.