Figure 1
Test System. a) Gene network [42] used as test system for illustrating the proposed methods. Solid arrows represent material flow, while dashed arrows indicate regulatory signals that either activate (+) or inhibit (-) a process. The network contains two genes, Gene 1 and 2. X1 is the mRNA produced from gene 1, X2 is the enzyme for which the gene codes, and X3 is an inducer protein catalyzed by X2. X4 is the mRNA produced from Gene 2 and X5 is a regulator protein for which the gene codes. Positive feedback from X3 and negative feedback from X5 are assumed in the production of mRNAs from the two genes. b) S-system model of the gene network, according to Hlavacek and Savageau [42] and Kikuchi et al. [21].