Stefan BraunewellReliability and Evolvability of GeneticRegulatory NetworksReliability and Evolvability of Genetic RegulatoryNetworksVom Fachbereich fur Physik und Elektrotechnik¨der Universitat¨ Bremenzur Erlangung des akademischen Grades einesDoktor der Naturwissenschaften (Dr. rer. nat.)genehmigte DissertationvonStefan Braunewell1. Gutachter: Prof. Dr. rer. nat. S. Bornholdt2.hter: Prof. Dr. rer. nat. K. PawelzikEingereicht am: 11.3.2008Tag des Promotionskolloquiums: 23.4.2008Abstract:Reliability and Evolvability of Genetic Regulatory NetworksLiving organisms are remarkably robust despite fluctuating concentrations of functionalmolecules in the cell and changing environmental conditions. In the biological literature,the question how organisms cope with this stochasticity has been investigated in theoryand experiment in specific organisms. To identify and understand general mechanismsthat facilitate reliable dynamical behavior, computer modelling can be useful to investigatespecific effects in isolation.In this thesis, the effect of the topological structure of transcriptional regulation networkson the reliability of the resulting dynamics is investigated in simple dynamical models. Theactivity of genes and proteins is modeled by discrete values. An extension of this discretedynamical model to continuous time is used and molecular fluctuations are implementedby random delays of signals.