Editing Gene expression programming (section)

===Populations of programs===
Like all evolutionary algorithms, gene expression programming works with populations of individuals, which in this case are computer programs. Therefore, some kind of initial population must be created to get things started. Subsequent populations are descendants, via [[#Selection and elitism|selection]] and [[#Reproduction with modification|genetic modification]], of the initial population.

In the genotype/phenotype system of gene expression programming, it is only necessary to create the simple linear chromosomes of the individuals without worrying about the structural soundness of the programs they code for, as their expression always results in syntactically correct programs.