In this section:
In nature, the phenotype has multiple levels of complexity, being the most complex the organism itself. But tRNAs, proteins, ribosomes, cells, and so forth, are also products of expression and all of them are ultimately encoded in the genome.
In contrast to nature, in GEP, the expression of the genetic information is very simple. Nonetheless, as we have seen in
section 2.1, GEP chromosomes can have different structural organizations and, therefore, the individuals encoded in those structures have obviously different degrees of complexity. The simplest individuals are encoded in a single gene, and the “organism” is, in this case, the product of one gene – an ET composed of only one subunit. In other cases, the “organism” is a multi-subunit ET in which the different subunits are linked together by a particular linking function or interaction. In other cases, the “organism” is a multi-subunit ET in which different combinations of subunits are linked together by particular linking functions, expressing the developmental program of a particular cell. In other cases, the “organism” emerges from the spatial organization of different sub-ETs. And, in other cases, the “organism” emerges from the interactions of conventional sub-ETs with smaller sub-ETs encoded in special domains, forming a complex network of interactions. However, in all cases, the whole “organism” is encoded in a linear genome.
In this section we will discuss different aspects of the expression of the genetic information in more detail, drawing attention to the different levels of phenotypic complexity.