FIGURE 1

Genetic network encodes molecular network, which in turn determines phenotypes. Although genes (except the regulatory sequences of the genes) do not directly participate in the molecular interactions, the potential interaction patterns (or what the molecular network is capable of doing) are encoded in genomic DNAs, and inherited from generation to generation. This concept is illustrated by the projections from genetic interactions to various types of molecular interactions between gene products, or between gene products and gene regulatory elements. However, both the genetic template and the actual steady states of the molecular interaction network are subject to change by environmental factors and developmental histories. Inside a system, the steady states of the molecular network directly correspond to the functional phenotype of the system, be it an organism, a tissue in an organisms, or other functional unit. When the changes affect the germlines of an organism, the changes become inheritable and play a role in evolution.