abstract = "The neutral theory of molecular evolution states that
the accumulation of neutral mutations in the genome is
fundamental for evolution to occur. The genetic
representation of gene expression programming, an
artificial genotype/phenotype system, not only allows
the existence of non-coding regions in the genome where
neutral mutations can accumulate but also allows the
controlled manipulation of both the number and the
extent of these non-coding regions. Therefore, gene
expression programming is an ideal artificial system
where the neutral theory of evolution can be tested in
order to gain some insights into the workings of
artificial evolutionary systems. The results presented
in this work show beyond any doubt that the existence
of neutral regions in the genome is fundamental for
evolution to occur efficiently.",