Meanings of 'life'

    Synthetic biology provides a welcome antidote to chronic vitalism.

    Many a technology has at some time or another been deemed an affront to God, but perhaps none invites the accusation as directly as synthetic biology. Only a deity predisposed to cut-and-paste would suffer any serious challenge from genetic engineering as it has been practised in the past. But the efforts to design living organisms from scratch — either with a wholly artificial genome made by DNA synthesis technology or, more ambitiously, by using non-natural, bespoke molecular machinery — really might seem to justify the suggestion, made recently by the ETC Group, an environmental pressure group based in Ottawa, Canada, that “for the first time, God has competition”.

    That accusation was levelled at scientists from the J. Craig Venter Institute in Rockville, Maryland, based on the suspicion that they had synthesized an organism with an artificial genome in the laboratory. The suspicion was unfounded, but this feat will surely be achieved in the next few years, judging from the advances reported earlier this month at the Kavli Futures Symposium in Ilulissat, Greenland, on the convergence of synthetic biology and nanotechnology, and the progress towards artificial cells.

    But should such efforts be regarded as 'creating life'? The idea that such creation is a momentous step has deep roots running from the medieval homunculus portrayed by Paracelsus and the golem of Jewish legend to the modern faustian myth of Frankenstein. It will surely be hard to uproot. This is unfortunate, as the idea is close to meaningless.

    “It would be a service to more than synthetic biology if we might now be permitted to dismiss the idea that life is a precise scientific concept.”

    There is a popular notion that life is something that appears when a clear threshold is crossed. One might have hoped that such perceptions of a need for a qualitative difference between inert and living matter — such vitalism — would have been interred alongside the pre-darwinian belief that organisms are generated spontaneously from decaying matter. Scientists who regard themselves as well beyond such beliefs nevertheless bolster them when they attempt to draw up criteria for what constitutes 'life'. It would be a service to more than synthetic biology if we might now be permitted to dismiss the idea that life is a precise scientific concept.

    One of the broader cultural benefits of attempts to make artificial cells is that they force us to confront the contextual contingency of this troublesome idea. The trigger for the ETC Group's protest was a patent filed by the Venter Institute in October 2006 on a “minimal bacterial genome” — a subset of genes, identified in Mycoplasma genitalium, required for the organism to be viable “in a rich bacterial culture medium”. That last sounds like a detail, but is in fact essential. The minimal requirements depend on the environment — on what the organism does and doesn't have to synthesize, for example, and what stresses it experiences. Too much minimization and you end up with cells on life support. And participants at the Greenland meeting added the reminder that cells do not live alone, but in colonies and, in general, in ecosystems. Life is not a solitary pursuit, nor can evolution happen without the opportunity for competition.

    Synthetic biology's view of life as a molecular process lacking moral thresholds at the level of the cell is a powerful one. And it can and perhaps should be invoked to challenge characterizations of life that are sometimes used to defend religious dogma about the embryo. If this view undermines the notion that a 'divine spark' abruptly gives value to a fertilized egg — recognizing as it does that the formation of a new being is gradual, contingent and precarious — then the role of the term 'life' in that debate might acquire the ambiguity that it has always warranted.

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    Meanings of 'life'. Nature 447, 1031–1032 (2007).

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