Who or What Plays the Music of DNA? - Evolution News & Views

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Who or What Plays the Music of DNA?

As I was driving in to work, the local NPR station had on an interview with a guy who's involved with gathering billions of seeds of various plant varieties into a "doomsday vault." It is on a remote Norwegian island and intended as a precaution against the presumed devastations of global warming. There were few surprises in the conversation -- the grim mood was well suited to the NPR target audience, which eats this stuff up -- apart from one rather interesting question from a listener. The guest, Cary Fowler of the Global Crop Diversity Trust, was asked why his group bothers with seeds. In the future, won't we be able to reconstitute life from the digital code of DNA?

Not necessarily, explained Fowler. He offered a few cryptic but telling comments about the complexities of gene expression, and how simply knowing the DNA sequence of a plant (or animal) may never be sufficient to generate life. Why? Part of the answer, implying a strong challenge to materialist explanations of life's evolution, is suggested in a recent and illuminating essay, "Getting Over the Code Delusion," in the Ethics and Public Policy Center journal, The New Atlantis.

Rare is the technical if otherwise quite accessible article that gives chills like this one does. Steve Talbott, a senior researcher at the Nature Institute, takes aim at the still-widespread illusion that DNA maps the construction of a living creature. In a 1992 essay, Nobel Prize-winning geneticist Walter Gilbert crowed that the time will come when a person will be able to say, of a human DNA sequence inscribed on a computer disk, "Here is a human being; it's me!" How utterly naïve that has since been revealed to be.

Richard Dawkins calls DNA "a remarkable feat of digital information technology," on the model of a computer albeit one that programs itself. Yet the burden of Talbott's article is to show why the whole computer metaphor is inadequate. If you want a better one, the really apt metaphor would be drawn from the art of dance -- or I'd say, music -- with all that implies by way of purpose, agency, and expression.

Linearly conceived DNA coding by itself doesn't suffice -- nowhere near so -- to orchestrate the building of proteins from amino acids, never mind a fully formed living creature. The study of the additional, inheritable information that's needed is called epigenetics. Where does that information reside? You might innocently picture the added information (epi- means "over" or "above") like a document you slip into a book on your bookshelf. It's a supplement to the book, over and above what's bound between the covers. To access the added information, it is just a matter of finding the right book on the shelf and opening it up. But this is totally wrong.

From Talbott's description, I am not sure that the word "information" really captures it either. What's at issue is gene expression -- when a given gene will be "expressed," or activated for translation into RNA and proteins, and when it will be unexpressed, or quiescent. Don't picture something simple and mechanical here like a player piano that "plays itself" by unspooling a roll of pre-perforated paper.

Driven by various "yet unknown signals and forces," arranging itself into incredibly tight, intricate and synchronized geometries "that researchers have yet to visualize in any detail," the chromosome is "engaged in a highly effective spatial performance. It is a living, writhing, gesturing expression of its cellular environment....The chromosome, like everything else in the cell, is itself a manifestation of life, not a logic or mechanism explaining life....[I]t's hard to ignore the active principle -- some would say the agency or being -- coordinating the movements."

Talbott writes of the way gene expression is "choreographed" through, for example, the behavior of the nucleosomes on which DNA is spooled, mediating between "gene and context -- a task requiring flexibility, a 'sense' of appropriate rhythm, and perhaps we could even say 'grace.'"

With our long-habituated reductionist, mechanistic expectations, we assume that if you dig deep enough into the organization of life, you will come across something like the ultimately dead mechanism of the self-playing piano. What you find instead is that "Things do not become simpler, less organic, less animate. The explanatory task at the bottom is essentially the same as the one higher up."

Thinking of the cell as running software, while accurate at the level of DNA -- and deadly to Darwinism all by itself since software implies authorship -- gives us only part of the story. Molecular biology has written "'finis' to the misbegotten hope for a non-life foundation to life, even if the fact hasn't yet been widely announced." Rather than a player piano, it is as if a piano were being played by a skilled and sensitive musician -- say, an improvisational jazz pianist -- with the instrument itself responding to his touch not as the expression of an algorithm but of its own life force. There is a very minimal musical score, in the form of DNA, inadequate to describe the music being performed, and then there is the pianist himself engaged in an improvisation on a swiftly shifting suite of themes.

And this is only the construction of proteins we're talking about. It leaves out of the picture entirely the higher-level components -- tissues, organs, the whole body plan that draws all the lower-level stuff together into a coherent, functioning form. What we should really be talking about is not a lone piano but a vast orchestra under the directing guidance of an unknown conductor fulfilling an artistic vision, organizing and transcending the music of the assembly of individual players.

Neo-Darwinism, to retain any credibility at all, requires the reductionist picture of DNA as the player-piano score of a clanking, whirring dead machine. In the modern Darwinian myth, chance variations in the dead code are what creates the raw material on which the zombie-like process of natural selection performs its blind, mindless work. If life ultimately reflects life -- "relations, movement, and transformation," as Talbott puts it, expressing purpose and agency -- down to the lowest level of organization, this represents a huge, seemly insurmountable problem for materialism.