A synthetic creation story
Claims of 'synthetic life' reflect only our changing conception of what life is and how it might be made, says Philip Ball.
Last week's announcement of the 'chemical synthesis of a living organism' by Craig Venter and his colleagues at the J. Craig Venter Institute1 heads up a very long tradition. Claims such as this have been made throughout history.
That's not to cast aspersions on the new results. One can challenge the idea that Venter's bacterium stands apart from Darwinian evolution, modelled as it is on Mycoplasma mycoides. It is nonetheless an unprecedented triumph of biotechnological ingenuity.
But, set in a historical context, what the researchers have achieved is not so much a 'synthesis of life' as a semi-synthetic recreation of what we currently deem life to be. And, as with previous efforts, it should leave us questioning the adequacy of that view.
To see that the new results reiterate a perennial theme, consider the headline of the Boston Herald in 1899: "Creation of Life. Lower Animals Produced by Chemical Means." The article described how German biologist Jacques Loeb induced an unfertilized sea-urchin egg to divide and develop into a larva by treating it with salts.
Loeb went on to talk in earnest about "the artificial production of living matter", and he was not alone in blending his discovery with speculations about the de novo creation of life. In 1912, the physiologist Edward Albert Schäfer alluded optimistically to Loeb's results in his presidential address to the British Association, in which he expressed great optimism about "the possibility of the synthesis of living matter"2.
Such claims are commonly seen to imply that artificial human life is next on the agenda. It was a sign of the times that the New York Times credulously reported in 1910 that, "Prof. Herrera, a Mexican scientist, has succeeded in forming a human embryo by chemical combination". It is surely no coincidence that many media reports have compared Venter to Frankenstein, or that the British newspaper The Observer mistakenly suggested he has "succeeded in 'creating' human life for the first time".
What is life?
Beliefs about the feasibility of making artificial organisms have always been governed by the prevailing view of what life is. When the Universe was seen as an intrinsically fecund matrix, permitting bees and vermin to emerge from rotten flesh by spontaneous generation, it seemed natural to imagine that sentient beings might issue forth from insensate matter.
Mechanical models of biology developed during the seventeenth century fostered the idea that a 'spark of life' — after the discovery of electricity, literally that — might animate a suitably arranged assembly of organic parts.
The blossoming of chemistry and evolutionary theory in the nineteenth century, meanwhile, spurred a conviction that it was all about getting the recipe right, so that nature's diverse grandeur sprung from primordial colloidal jelly called protoplasm.
Yet each apparent leap forwards in this endeavour more or less coincided with a realization that the problem is not so simple.
Protoplasm appeared as organic chemists were beginning to erode the concept of vitalism and to appreciate the baffling constitution of organic matter. The claims of Loeb and Schäfer came just before tools for visualizing the subcellular world began to show the incredible complexity of life's microstructure.
And it was the same story for the next big splash in 'making life', when in 1953 Harold Urey and Stanley Miller announced their celebrated 'prebiotic soup' experiment, in which they conjured amino acids from simple raw materials. Some press reports regarded this as a new genesis, in principle if not in practice. Yet that same year saw the game-changing discovery of life's informational basis in the work of Crick and Watson. Now life was not so much about molecules, but about cracking, and perhaps then rewriting, the genetic code.
No more codes
Which brings us to Venter et al. Now that the field of genomics has fostered the belief that in sequencing genomes we are reading a 'book of life', it's easy to see why 'booting up' a wholly synthetic genome in a bacterial host should be popularly deemed a synthesis of life itself. Here the membranes, the cytoplasm — everything except the genes — are mere peripherals to the hard drive of life, whose algorithmic instructions need only be rejigged to produce new organisms.
But this latest work should encourage us to lay aside the very concepts of an 'artificial organism' and a 'synthesis of life'. Life is not a thing one makes, nor is it even a process that arises or is set in motion. It is a property we may choose to bestow, more or less colloquially, on certain organizations of matter.
'Life' in biology, rather like 'force' in physics, is a term carried over from a time when scientists thought quite differently, when it served as a makeshift bridge over the inexplicable.
Attempts to make a genuinely 'designed' genome, rather than one based on a naturally evolved bacterium, will remind us how sketchy our understanding is of the rules that govern the crucial interactions among genes and with other elements of living cells. In the post-genomics era, our ideas of where the real business of life resides are shifting again. We are moving away from a linear 'code' and towards something altogether more abstract, emergent and entangled.
So in marking yet another deepening appreciation of how life operates, the latest 'synthesis of life' seems likely to repeat the historical template.
Philip Ball's next book, Unnatural: The Heretic Idea of Making People, will be published next year by Bodley Head.
- Gibson, D. G. et al. Science doi:10.1126/science.1190719 (2010).
- Schäfer, E. A. Nature 90, 7-19 (1912).