 Annealing temperatures for each of the primer sets must be optimized to work correctly within a single reaction, and amplicon sizes, i.e., their base pair length, should be different enough to form distinct bands when visualized by gel electrophoresis.When producers, importers or authorities test a sample for the unintended presence of GMOs, they usually do not know which GMO to expect.While EU authorities prefer an event-specific approach to this problem, US authorities rely on construct-specific test schemes.