 DNA-based device construction, or what Benner and Sismour (2005) characterize more broadly as the engineering trend, explores the extent to which interchangeable and functionally distinct components can be designed and implemented in a modular fashion. The BioBrick Foundation is a paradigmatic example of this approach (biobricks.org). The guiding principles for this approach are standardization, decoupling, and abstraction of parts and functional descriptions (Endy 2005). Examples of DNA-based devices are the repressilator (Elowitz &amp; Leibler 2000, see  Section 2.1),  the synthetic toggle switch (Gardner et al. 2000; see  Section 2.3),  as well as production of synthetic artemisinin for antimalarial drugs (Keasling 2010). The orientation towards functional devices and machine-like control is also explicit in the so-called iGEM competition (Genetically Engineered Machine) where student teams compete in the task of constructing genetically engineered biological systems to address societal problems. Whether the ideal of constructing standardized and replaceable parts is compatible with biological complexity is an ongoing topic of debate  (Sections 2  and  3).