Intra- and interspecific variation in electrophoretic profiles of Tethya spp.: an integration to morfological classification system

Here we described an original protocol based on the comparison of the electrophoretic protein profiles of crude extracts from three different population of sponges of genus Tethya, i.e. Tethya aurantium (Ta), T. citrina (Tc) and T. meloni (Tm), collected in three Mediterranean sites located along the coast of Apulia (Italy) This protocol allows to support the taxonomic classification for the discrimination between sponge species that are hard to identify since they are phylogenetically close and present similar morphological features. The computerized images of Native-PAGE gels were analysed using the freeware 1D gel electrophoresis image analysis software GelAnalyzer (http://www.gelanalyzer.com) and for each crude extract the protein bands clearly defined were taken into consideration. The polymorphic bands were scored visually as either present (1) or absent (0). These data were used for the calculation of a similarity coefficient using the Jaccard coefficient similarity matrices. The data sets were analysed using DendroUPGMA, a dendrogram construction utility (http://gesnomes.urv.es/UPGMA/).