In James Whale’s 1931 film of “Frankenstein”, the monster is brought to life as his creator imagined God’s first creatures to have been: by lightning. “Behold!” Victor cries, as the storm lashes his laboratory and its metal armatures begin to glow. “The great ray that first brought life into the world.” A couple of decades later, in a ground-breaking foray into the science of life’s origins, the biochemist Stanley Miller used high-voltage sparks to produce some amino acids, the building blocks of proteins. His Chicago laboratory was less dramatic than Victor’s, but the idea was the same: a flask of gases represented the atmosphere of the early Earth; the sparks, its lightning.
There is lightning, too, in a wonderful new book by Nick Lane, a biochemist at University College London, and, I should add, a friend of mine. “The Vital Question”, rated “masterful”, “epic” and “scintillating” by the critics, contains as convincing an account of the origins of life as any now on offer. And it also contains lightning – but as a comparator, not an instigator. The strength of the electric field across the membranes that allow living things to capture the energy they need is a startling 30m volts per metre: the same sort of strength seen in the fields that tear open thunderclouds.
Lane belongs to a small and persuasive cabal that is using studies of the way cells access energy to gain insight into all sorts of questions, from why there are different sexes to why creatures grow old (and – a personal favourite – why birds age much more slowly than other creatures of their size). The cabal takes Theodosius Dobzhansky’s well-worn dictum, “Nothing in biology makes sense except in the light of evolution”, and adds that nothing in evolution makes sense except in the light of energetics.
At the centre of this view of the world is that membrane of lightning-like potential. Both of the primary processes by which cells get their energy, respiration and photosynthesis, depend on a flow of electrons through protein complexes in these membranes to move protons – hydrogen atoms from which the electrons have gone missing – across them. It is the return of the protons thus exiled which turns the energy gained from sunlight or food into something that the cell can access.
These processes are harder to grasp than those of DNA – as Watson and Crick noted in their first paper on the subject, once you see how the links between them bind a pair of DNA molecules into a double helix, each the template for its complement, the idea that molecules store information that can be read and copied is intuitively obvious. But if they are less pretty to look at and less easily understood, the membranes Lane writes about are, if anything, even more fundamental to an understanding of life, not least because they pre-date DNA. Indeed, they pre-date life.
Norman Pirie, a brilliantly eccentric biochemist, was one of the first to point out that laboratory studies revealed a continuum between life and death. These two words, he wrote in the 1930s, “still have a very definite meaning when used by poets, knackers or soldiers, but little or none when used to describe the phenomena observed in tissue culture, virus research and kinetic studies on interrelated enzyme systems.” One of the achievements of the school Nick Lane writes about is its application of this idea to the question of the origins of life, suggesting ways in which mineral membranes separating fluids with very different proton concentrations could have given rise to biological systems in which they would eventually be replaced with the sorts of membranes seen in cells today – going from pure geochemistry at the beginning to pure biochemistry at the end, with only the flow of energy constant throughout.
The implications of understanding life in this way far outstrip the span of a column. Even Lane’s magnificent book can scarcely contain them. But there is an overarching point that transcends the insights into everything from extraterrestrial life to three-parent babies that are on offer. From “Frankenstein” – and the electrochemical speculations that its author, Mary Shelley, took as her inspiration in 1818 – to Miller and beyond, electricity comes as the bolt from the blue that brings life to the inanimate. It is imagined acting almost as a soul – as what the pre-electric poet Pope, imagining the last moments of the emperor Hadrian, first dubbed a “vital spark”.
This new science undercuts such dualism. Energy is not an addition to life: it shapes it from the inside out, and from the point of origin. DNA allows living things to copy themselves, and fixes the small variations on which evolution can act; the membranes enable the ceaseless production that underlies all that reproduction. It is this process, not some abstract set of sequences, which explains the way biology is – an unending, exciting and excited flow.
It may be that the question “What is life?” is, for reasons like those given by Pirie, a foolish attempt to pin down an essentially abstract noun. The wiser question is “What is living?” And the answer, on current evidence, is a current.