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units for time, unrelated to measurementprocedures. It is not a physical prediction.

Furthermore, the variation principlesproposed as underlying the physics involvethe metric tensor in raising and loweringindices to create scalars — and hence buildinto the foundations of the theory the invari-ance of the speed of light (the metric deter-mines the speed of wave propagation). We aregiven no reason why any broken symmetriesassociated with special solutions of the result-ing equations will give a causal explanationfor a varying speed of light — but this variation is the arbitrary postulate of VSLtheory. And apart from the part of the action determining variation of the speed of light (independently of Maxwell’s equations), theexplicit occurrence of the speed of light in theVSL variational principle proposed is only ina ratio with the gravitational constant G — sothis is just a varying-G theory in disguise.

Developments that could make VSLviable, such as further investigation of thetime variation of the fine-structure constant,of two-metric theories, of an altered versionof the symmetry group underlying relativitytheory, or through a string-theory motiva-tion for varying ‘constants’, need to provide a clear relation to space and time measure-ment, as well as a physical reason (based insome version of Maxwell’s equations) for thespeed of light to vary. It is a pity that Magueijodoes not mention progress made in thesedirections by workers other than himself andhis own collaborators. ■

George Ellis is in the Department of Mathematics,University of Cape Town, Rondebosch 7700, Cape Town, South Africa.

C’est la vie?The Delphic Boat: What GenomesTell Usby Antoine Danchin, transl. Alison QuayleHarvard University Press: 2003. 368 pp. $35,£23.50, E35

Axel Meyer

This contribution from old Europe’s grandenation discusses genomics, the politics ofgenome research, the philosophy of science,and the not-so-small question of the nature

of life. The first problem faced by the author,Antoine Danchin of the Pasteur Institute in Paris, France, is how best to describe agenome. He borrows from Greek mythologythe tale of the oracle of Delphi, which askedwhether a boat that has had all of its planksreplaced over time is still the original boat ornot (to its owner, who watched its evolution,it would be). Danchin makes the point that itis the relationship of the planks (or in thecase of the genome, the genes) to each otherthat determines what kind of boat (genome)it is; individual planks are less important indetermining the essence of a boat.

It has been known for some time that agenome is not merely a set of independentgenes arranged like pearls on a string. Theessence of a genome has been described as a code, a blueprint, a musical score and a set of instructions. All of these metaphors are used in an attempt to convey the notionthat a genome is more than the sum of its parts.

From an evolutionary biologist’s point of view, each organism’s genome (includingour own) is a record of its evolutionary history: genomes are shaped by symbiosesand hybridizations, as well as by naturalselection. In attempting to understand theorigin and diversification of life, the increasein complexity during ontogenetic develop-ment, and even more straightforward questions such as the genetic bases of dis-eases, the study of individual genes will reachits limits and fall short of a more holistic appreciation that considers the entiregenome (and the entire phenotype). Genes‘talk’ to one another, regulating each other’sexpression in response to environmentalconditions and the prevailing ontogenetic or metabolic state of the cell or organism.Genes are also affected by their position inthe chromosome, by the base composition

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More than the sum of its parts: the relationship between the planks determines what kind of boat it is.

Mantids are ambush predatorsthat keep still and wait forother insects to approachbefore striking and feeding onthem. Like other mantids, thefemale mantis Harpagomantisdiscolor shown here iscamouflaged and remainsmotionless, or rocks slightlyfrom side to side to side as ifswaying in the breeze, all thewhile keeping its forelegsfolded in a mannerreminiscent of prayer. Whenanother insect comes close,the mantis snatches it andholds it in a pincer-like gripwhile devouring it alive.Mantids are just one of thearthropod orders included in The New Encyclopedia ofInsects and their Allies (OxfordUniversity Press, £25), editedby Christopher O’Toole.

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of surrounding DNA, and by other “local climates”, as Danchin puts it, that mightinfluence their tempo and mode of evolutionor level of expression.

Early and overly simplistic notions thatthe determination of a genome sequence (or “genome text”, in Danchin’s words) willdetermine precisely how an organism workshave long gone the way of the dodo. In silicoanalyses — computer analyses of genomicinformation as an alternative to in vivo or in vitro studies — are now an establishedfield, known as bioinformatics. They arelargely based on comparative (evolutionary)approaches. The hardest route, but in myopinion the one that offers the brightestfuture and the most intellectual profit, mightbe comparative and functional-genomicanalyses of the architecture of genetic cas-cades and networks. The hope, and there are encouraging signs for this, is that thereare commonalities and higher-level organi-zational principles, or even that this field of enquiry might reveal some of biology’smore elusive laws.

Of course, no book can be written foreverybody, but many readers might like toknow what, if anything, genomics can tell usabout the meaning of life. Various features of this book will be of varying interest to different audiences. Given the big issues itaddresses, The Delphic Boat is apparentlyintended for a wide, non-specialist reader-ship. Descriptions of the idiosyncrasies,foibles, imperfections and particular aspectsof the politics of French grant-funding agencies make the book a lively read anddemonstrate to the uninitiated reader thatpolitics has an unpleasantly large role in science. Danchin also stresses the importantcontributions of French researchers to thevarious advances in genomics.

Although these often rather personal andhistorical sidelines might be of particularinterest to science historians or researchersworking on microbial genomics, these spe-cialist readers would not want to be botheredwith explanations of how the polymerasechain reaction works, for example. But suchtechniques and other introductory andbackground information will presumably beof interest to the non-specialist reader whowould like to discover what genomics is allabout. This kind of reader might need moreexplanation of some of the basic concepts in genetics and genomics, however. In someplaces, rather specific jargon is used whichmight confuse general readers. And discus-sion of alternative DNA-sequencing tech-niques is probably beyond most uninitiatedreaders. ‘Automatic’ sequencing techniqueshave been used pretty much exclusively ingenomics for 15 years now, but one of the few figures in the book shows a ‘manual’ gel with radioactively labelled DNA —rather a relic of the past. The lay reader would have profited from the inclusion of

an electropherogram instead, if the budgethad stretched to colour figures.

These limitations aside, Danchin pro-vides an authoritative and impressively multidisciplinary treatment of many aspectsof genomics, and his provocative thinkingabout the raison d’être captured my interest. I suspect that it will do the same for manyreaders from a large number of scientific disciplines, not only biological ones. ■

Axel Meyer is in the Department of Biology,University of Konstanz, 78457 Konstanz, Germany.

Music

Sounds from spaceSun Ringsby Terry RileyPerformed by the Kronos Quartet

Juliane C. Mössinger

During the First World War, the Germanphysicist Heinrich Barkhausen accidentallymade the first recording of strange‘whistling’ sounds while tapping Britishphones. He reported the peculiar tones(Phys. Z. 20, 401; 1919), but could notexplain them at the time.

The ‘whistler’ is just one of many spacesounds that form the inspiration for TerryRiley’s composition Sun Rings, performed by the Kronos Quartet at the Barbican Centre in London on 22 March 2003, withfurther performances to follow in seven US cities over the coming months. The work, which was commissioned by NASA’sarts programme, is based on the collected space recordings of Don Gurnett, an astro-physicist at Iowa State University, whoseplasma-wave receivers have been travelling

on various spacecraft for the past 40 years. Plasma waves are in low radio frequencies.

When converted to audible sound waves, patterns emerge — like the ‘whistler’, a rapidly descending tone caused by lightningdischarges. Another is the ‘dawn chorus’,brief, rising-frequency tones that sound likethe chirping of birds and which are producedby electrons trapped in magnetic fields surrounding planets.

For the performance, the theatre isplunged into darkness. The quartet on stageis surrounded by thin silver sticks adornedwith dimly glowing, star-like lamps. Behindthe musicians, digital images of edited andoriginal NASA footage, arranged by visualdesigner Willie Williams, are projected ontoa giant screen.

The ten ‘spacescapes’ that make up Sun Rings incorporate the original soundsrecorded by the plasma-wave receivers. Thestring quartet also mimics them. But Riley’sinteresting and diverse composition is muchmore than this. He has done what scientistsconsider unthinkable, explained Gurnett inhis pre-performance talk: he has manipu-lated original data and changed thembeyond recognition. Riley’s journey is largely about humans as they explore outer space to gain an awareness of their Solar Systemneighbourhood. The human dimension isemphasized by the addition of a choir insome of the movements.

‘One Earth, one people, one love,’ afemale voice declares. Images about life onEarth are displayed on the huge screenbehind the Kronos Quartet. They are part ofthe message sent on Voyager through space.While bombs are dropping on Iraq, ‘oneEarth, one people, one love’ seems to be further away from humanity than Voyagercould ever travel. ■

Juliane C. Mössinger is a physics editor at Nature.

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String theory? The Kronos Quartet perform Sun Rings against a backdrop of images of the Universe.

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