Due to the unconstrained genotype/phenotype mapping of GEP, several genetic operators can be easily implemented and Ferreira [3] uses seven: mutation, three kinds of transposition (IS, RIS and gene transposition), and three kinds of recombination (one-point, two-point and gene recombination). Most of these operators are important per se, and here they are going to be analyzed separately, but one of them – gene transposition – is only significant if used in conjunction with recombination and therefore will not be analyzed here.

The performance of six GEP operators is shown in Figure 1, and it clearly shows that mutation is by far the single most powerful operator, followed by RIS transposition and IS transposition, whereas recombination is the less powerful operator with gene recombination at the end of the line.

Figure 1. The transforming power of mutation, transposition, and crossover.