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Center for Nonlinear Studies |
The physical basis for complex phenotypes is the context-dependent expression of the organism’s genome. The context is provided by the life cycle of the organism; the molecular mechanisms of gene regulation interpret that context and orchestrate appropriate responses. The regulation of many gene systems has been studied in detail, and the results have revealed an enormous diversity of molecular elements and circuits. We are just beginning to understand the functional implications of such variations in design and to grasp the factors that have influenced their evolution. The relationship of these variations in design to the phenotype of the organism is even less clear. A quantitative systems approach is required to elucidate these relationships, for without it our understanding will remain descriptive and lack predictive value. In this talk I will first review two biological design principles that have been revealed by such an approach. These involve the coupling between elementary gene circuits and the metabolic connectivity within such circuits. These features of the design have a profound influence on the dynamics of gene expression. Finally, I will examine the implications of design for the evolution of a specific, well-studied gene circuit. The results provide surprising predictions concerning the organism’s phenotype and habitat.
Host: Robert Ecke, CNLS