to construct using the more conventional recombinant DNA1 (rDNA) techniques of the 1970s and 1980s. In the past decade or two newer approaches—combining engineering and biological techniques—have enhanced researchers’ abilities to manipulate DNA. These new synthetic techniques allow for genes and long chains of DNA to be designed and constructed from scratch using a computer and relevant chemical compounds, rather than by employing a “trial-and-error” approach to the identification and insertion of pieces of existing genes from living cells into a novel host environment.
In May 2010, researchers at the J. Craig Venter Institute announced that they had produced the first functional, self-replicating, bacterium whose entire nuclear genome had been synthesized artificially in the laboratory, albeit using a naturally occurring genome sequence as a template (Gibson et al., 2010). While the achievement did not, as some media reports at the time suggested, represent the “creation of life,” it did propel the nascent field of synthetic biology into the mainstream, and generated a number of questions and much speculation about the potential power, utility and risks associated with work in this field.
Although biologists may have a long way to go before they have enough knowledge and the tools necessary to design and build life, the emerging field of synthetic biology has already reduced several novel products and lead compounds for drugs and vaccines, fuel, biofabrication of materials, and other industrial applications. Most, if not all, of these products and compounds are being generated via the type of top-down approach, with scientists reengineering existing cells to do things that they do not normally do. By inserting the genetic machinery for metabolic pathways into Escherichia coli and other host organisms, scientists are attempting to create microbial bio-factories for the production of pharmaceutical ingredients, flavors, fragrants, and other chemical products (Ro et al., 2006). The goals also include compounds and cells with new phenotypes and functionalities, such as cells that can produce carbon-neutral biological fuels with properties that are similar to those of petroleum-based fuels (Fortman et al., 2008; Keasling, 2010) and novel drugs (Li and Vederas, 2009).
The United Kingdom’s Royal Academy of Engineering observed that “[s]ystems biology aims to study natural biological systems as a whole, often with a biomedical focus, and uses simulation and modeling tools in comparisons with experimental information. Synthetic biology aims to build novel and artificial biological parts, devices and systems. Many of the same methods are used and as such there is a close relationship between synthetic biology and systems biology. But in synthetic biology, the methods are used as the basis for engineering applications” (Royal Academy of Engineering, 2009, emphasis added). While both disciplines use similar approaches, systems biology uses these approaches to better understand the inner-workings of life, whereas synthetic biology emphasizes
1 Recombinant DNA: DNA that is created in the laboratory by splicing together DNA molecules from different sources, usually for replication in a host organism.