environments and challenges. Modularity appears to be a useful feature of evolvable, rapidly-adapting systems—some biological systems and even components are highly modular, such that components and sub-components can be rapidly swapped in and out to generate new functions. Eukaryotic signaling systems are a good example, but prokaryotes rely on much less modular systems that nonetheless serve them very well. Are there costs of evolvability in terms of system performance?
When and how can evolutionary methods contribute to design of synthetic systems?
How can evolutionary methods be best integrated with “rational” design, including computational design? What is the role of modeling?
Are there design objectives that can be addressed only through evolutionary strategies? Are there objectives for which evolutionary strategies are unnecessary?
What are the best targets for evolutionary optimization? Molecules? Circuits? Organisms?
What technologies and tools will be needed for rapid, efficient evolutionary optimization?
What strategies can we use to overcome the tendency of synthetic biological systems to mutate and escape programmed control?
How do we design systems and host organisms to ensure genetic stability?
How can we best understand mechanisms and consequences of mutation and develop routes for repair that enable designed functionality to be maintained?
To what extent is it important to pursue strategies for designing evolvable systems? What are the key features?
Haseltine EL, Arnold FH. Synthetic gene circuits: design with directed evolution. Annu Rev Biophys Biomol Struct 2007;36:1-19: http://arjournals.annualreviews.org/doi/full/10.1146/annurev.biophys.36.040306.132600?amp;searchHistoryKey=%24%7BsearchHistoryKey%7D. Accessed online 28 July 2009.