Changing fashions in genes

Among the imponderables which pit creationists against godless academics, the question of the origin of life has generated its…

Among the imponderables which pit creationists against godless academics, the question of the origin of life has generated its own addling literature, encompassing microbiology, theoretical and molecular chemistry, information theory and even computer models based on an emerging, rather promiscuous, ill-defined complexity theory. The latter seeks to explain, among other things, how living organisms exhibit such staggeringly intricate chemical and higher-order behaviour - behaviour which somehow emerges from simple underlying principles.

The earliest life forms left no fossils, so Woolfson, who holds down two fellowships in Cambridge, writes from a highly theoretical angle, chiselling from mountains of speculative literature. His central thesis is that genes are neither required, nor indeed adequate, to explain the very earliest emergence of life.

He quotes Freeman Dyson: "The primal characteristic of life . . . is homeostasis" - a stable, dynamic equilibrium - "rather than self-replication." Apart from drawing inspiration from experimentally observed "auto-catalytic" chemical networks - and the weird, ancient ecologies of hydro-thermal vents on the seafloor - Woolfson cites little hard chemistry as he postulates whether the earliest life forms arose, free-floating in some primordial "soup", or enclosed within fatty micelles or membranes; or indeed whether they "lived" for nanoseconds, days, or months.

Like many, he argues that such life-systems may seem to defy the Second Law of Thermodynamics - which, in terms of entropy, states that all matter tends towards its most chaotic, most disordered state. But there is no paradox when you consider that such systems sustain themselves by creating more disorder in the environment.

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He cites Max Planck's classical distinction between two types of order: (i) order from disorder (the collective, higher-order behaviour of chaotic entities such as, say, the patterns formed in sand in a vibrating tray); or (ii) order built on pre-existing order, e.g., life. Indeed, each genetic programme is itself programmed by pre-existing precursor programmes - what Dawkins calls the "digital river of genetic information". But how could genes have evolved in the first place? Using (not entirely appropriate) analogies from later evolutionary history, Woolfson cites "naked gene" viruses which inject their DNA into other genomes. He surmises that DNA and RNA are highly evolved forms of some primordial, self-replicating, "digital" code-carrying polymer, which somehow "parasitised" geneless proto-life forms. This "digital inocculum" must have arisen from self-replicating, but non-coding proto-genes. Some may have acquired the capacity to code for the synthesis of other chemicals - just as DNA codes for the synthesis of proteins in modern cells - through selective feedback.

The adaptive benefits of codification and high-fidelity self-replication may have seen these pre-genes emerge as true genes, due to some form of natural selection. Such an innovation would have caused a revolution, enabling proto-life lineages to exploit vast new areas of complexity through the quite formidable power of combinatorial chemistry.

Certainly, something predated modern genes which, encoded in DNA, carry none of the machinery of self-replication, but rather depend on an intracellular environment, with its battery of enzymes, building blocks, ribosomes, and RNA intermediaries. However the RNA chemistry which has emerged over the past two decades has proved that RNA can exhibit catalytic behaviour (as protein-enzymes do in cells). Woolfson's pregene "digital polymers" may have acted just so - as catalysts as well as codifiers.

Unfortunately, Woolfson raises many more questions than he answers, but just as the "selfish gene" theory back-flipped existing notions of Darwinian evolution, he and others are pushing the envelope in terms of the transformative power of information. Inspired by computer models, he sometimes veers into eschatology, leaving you with that bubble gum-on-an-empty-stomach feeling you get from reading too much Marvin Minsky.

But this is no casual punter's edifying jaunt through the field. If one has the vocabulary, there is much to mull over, but a great deal of it is methodical, hardcore repetition and extrapolation of information theory - scarcely enlivened by ditzy, unhelpful 10-page analogies of infinite "gene kit" hyper-marts, or robotic schoolboys on scramble nets to describe mathematical realms of possibility. The dry-as-dust prose is also unrelieved by any illustrations, or indeed index (other than an extensive bibliography). Although this book yields many insights, the general reader will emerge with little more than a headache.

Mic Moroney is a critic and journalist