Substitution of fish species detected by thin-layer isoelectric focusing and a computer-assisted method for the evaluation of gels

Fourteen fish species susceptible to substitution were analysed by the thin -layer isoelectric focusing technique on polyacrylamide gels of pH 3.5-9.5. Four fish per species were run on the same gel to verify the possibility t o differentiate them according to their protein banding patterns. The occur rence of intraspecific differences due either to electrophoretic variations or to protein polymorphism was also observed. in fact, some of them showed few dissimilarities among their protein profiles. However, the differentia tion was possible for all species, even for those belonging to the same ord er, family and genus. Computer-based tools combined with statistical analys is were implemented and usefully applied to avoid a subjective evaluation o f the isoelectric focusing gels, and to verify the reliability of the preli minary visual comparison of protein patterns. (C) 2000 Elsevier Science B.V . All rights reserved.