Defining the concept
This exciting field is evolving so rapidly that no widely accepted definitions exist. Common to many explanations is the idea of synthetic biology as the application of engineering principles to the fundamental components of biology.
All living organisms contain an instruction set that determines what they look like and what they do. These instructions are encoded in the organisms's DNA -- long and complex strings of molecules embedded in every living cell. This is an organism's genetic code (or "genome").
Humans have been altering the genetic code of plants and animals for millennia, by selectively breeding individuals with desirable features. As biotechnologists have learned more about how to read and manipulate this code, they have begun to take genetic information associated with useful features from one organism, and add it into another one. This is the basis of genetic engineering, and has allowed researchers to speed up the process of developing new breeds of plants and animals.
More recent advances however, have enabled scientists to make new sequences of DNA from scratch. By combining these advances with the principles of modern engineering, scientists can now use computers and laboratory chemicals to design organisms that do new things--like produce biofuels or excrete the precursors of medical drugs. To many people, this is the essence of synthetic biology.
Below we have listed several of the more commonly referenced definitions:
"Synthetic biology is a) the design and construction of new biological parts, devices and systems and b) the re-design of existing natural biological systems for useful purposes."
Source: Synthetic Biology.org
"Synthetic biology is an emerging area of research that can broadly be described as the design and construction of novel artificial biological pathways, organisms or devices, or the redesign of existing natural biological systems."
Source: UK Royal Society
"Synthetic biology is a maturing scientific discipline that combines science and engineering in order to design and build novel biological functions and systems. This includes the design and construction of new biological parts, devices, and systems (e.g., tumor-seeking microbes for cancer treatment), as well as the re-design of existing, natural biological systems for useful purposes (e.g., photosynthetic systems to produce energy). As envisioned by SynBERC, synthetic biology is perhaps best defined by some of its hallmark characteristics: predictable, off-the-shelf parts and devices with standard connections, robust biological chassis (such as yeast and E. coli) that readily accept those parts and devices, standards for assembling components into increasingly sophisticated and functional systems and open-source availability and development of parts, devices, and chassis."
"Synthetic biology is the engineering of biology: the synthesis of complex, biologically based (or inspired) systems which display functions that do not exist in nature. This engineering perspective may be applied at all levels of the hierarchy of biological structures – from individual molecules to whole cells, tissues and organisms. In essence, synthetic biology will enable the design of ‘biological systems’ in a rational and systematic way."