<p>Alginate is known to be a commercially valuable polysaccharide, of great importance in industries such as food, cosmetics, medicine and pharmaceuticals. It is obtained commercially by harvesting brown algae. The final step in the alginate biochemical pathway involves the epimerization of D-mannuronic residues into L-guluronic residues, catalyzed by the enzyme mannuronan-C5-epimerase. This final step has been found to be responsible for controlling the physicochemical properties of the produced alginate. This study is the first to characterize the genes encoding for the enzyme mannuronan-C5- epimerase in the Northern, Southern and Wellington lineages of the brown alga Lessonia variegata (Phaeophyceae). The gene of interest was amplified by standard PCR and cloning. Cloning PCR results revealed the presence of two distinct copies of the gene in Lessonia variegata. The coding region of the copies was found to be very conserved with very little sequence variation. The Lessonia variegata sequences were compared with those of Laminaria digitata and Saccharina japonica, which indicated that at least one gene duplication event has occurred in Lessonia variegata, leading to the formation of two gene duplicates. The possible mechanisms by which the gene paralogs may control the structure and function of the produced alginate have been discussed.</p>
DNA variation in the phenotypically-diverse brown alga Saccharina japonica
