The DNA that Venter’s team inserted into a bacteria, in his recently reported break-through in synthetic biology, was entirely synthetic – “Our cell has been totally derived from four bottles of chemicals”, he is quoted as saying. It’s this aspect that underlies the comment from Arthur Caplan that I quoted in my last post, that “Venter’s achievement would seem to extinguish the argument that life requires a special force or power to exist. This makes it one of the most important scientific achievements in the history of mankind.” Well, this is one view. But the idea that some special quality separates matter of biological origin from synthetic chemicals – chemical vitalism – is more usually assumed to have been killed by Wöhler’s synthesis of urea in 1828.
But while Venter is putting a stake through the heart of the long-dead doctrine of chemical vitalism, I wonder whether he’s allowed another kind of vitalism to slip in through the back door, as it were. The idea that his cells are entirely synthetic depends on a particular view of the flow of information – we have the sequence of his genome stored on his computer, this information is given physical realisation through the synthesis of the information carrying molecule DNA, and it is this information, when inserted into the lifeless husk, the shell of a bacteria whose own DNA has been removed, that sparks that cell into life, re-animating the cell under the control of the new DNA. In language Venter and others often use, the cell is “booted up”, as a dead computer with a corrupted operating system is restored to life with a new system disk. This idea that the spark of life is imparted by the information of the DNA seems perilously close to another kind of vitalism – let’s call it “digital vitalism”.
But does DNA control the cell, or does the cell control the DNA? Certainly, until Venter’s DNA molecule is introduced into its bacterial host, it is simply a lifeless polymer. It’s the machinery of the cell that reads the DNA and synthesises the protein molecules whose sequences are encoded within it. In many cases, it’s the regulatory apparatus of the cell that controls when that reading and synthesis is done – an enzyme is a tool, so there’s no point making it unless it is needed. Here the DNA seems less like a controller directing the operation of the cell, and more like a resource for the cell to draw on when necessary. And, it seems, bacteria endlessly swap bits of DNA with each other, allowing the fast spread of particularly useful tools, like resistance to antibiotics. This isn’t to deny that DNA is absolutely central to life of all sorts – without it the cell can’t renew itself, much less reproduce – but perhaps the relationship between the DNA and the rest of the cell is less asymmetric and more entangled than this talk of control implies.
How much do we need to worry about a few arguable metaphors? Here, more than usually, because it is these ideas of complete control and the reduction of biology to the digital domain that are so central in investing the visions of synthetic biology with such power.