Parsing was all-important. If the codons in the string
ACGGATCTAGACCT…
did not overlap, then the triplets separated:
ACG GAT CTA GAC…
But if every codon shared two bases with each neighbor, the same string would group into entirely different words:
ACG CGG GGA GAT ATC TCT CTA TAG…
This Ml overlap packed more information into each DNA half-strand but attached restrictions on the ordering of code words. The beauty of Gamow's diamond code lent early favor to overlap models. When his scheme failed to comply with experiment, Ga-mow withdrew it but suggested another full overlap in its place. But by 1957, such schemes had been all but discarded. In full overlap, every individual base appears in two adjacent codons:
CGAT → CGA GAT → x-y
A mutation altering the single base G would change both codon words, and thus both amino acids x and y in the synthesized enzyme. Even single mutations would then produce at least two amino acid divergences. Yet Ingram's famous sickle-cell hemoglobin structure differed from normal hemoglobin by only one amino. This argument damning full overlap contained the germ of an elegant and overlooked idea. A mutation, traced from nucleic acid to that text's observable protein translation, might be the leverage needed to manufacture a rosetta. The code could be cracked by tracing how it read its message's errors. One of the most powerful ideas in the infant science: the power of the traceable, testable blit. If the string itself was too complex to read, a small mistake in it might nevertheless show up as a discernible, translated difference.
Error lay at the source of all change, all species experiment. It was the author of all the still emerging, undesignable variations on life. Ressler's gift lay in understanding that he stood on the threshold not just of uniting chemistry with inheritance, but of joining these both to the grandiose Darwinian mutation. Tiny, cumulated, field-tested errors were all that accounted for the change from one species to another — a half-dozen chromosomal inversions between us and the nearest ape. Advance by analogy: induce a small alteration, note what value the process assigns that one ripple. The most baldly obvious idea imaginable. Yet as that most quotable biologist J. B. S. Haldane, instrumental in linking population genetics to evolution, who attributed all sonnet-writing to the microscopic speck of sex chromosome, once said: "It is, in my opinion, worth while devoting some energy to proving the obvious."
Today in History
Although I still lived in the height of summer, the days had already gone into gradual decline, at first unfelt, then undeniable, shuttling back to their opposite number. The longest day of the year is also the day diminishing sets in. In 1983, I lagged behind the official sunset posted in the almanac. As late as September, I felt the expectation brought on by sky remaining light late into evening.
Like the student who in the course of a perfunctory thesis finds a remarkable, forgotten book, I took possession of my discovery. Dr. Ressler worked his way into my daily conversation. In a slow period at the Reference Desk, I asked my colleague Mr. Scott what he knew about mutation dating. He had a master's in anthro, which suddenly seemed to me a half brother to genetics by incest. He put his fatherly arm around me and said, "Dear, I'm afraid M.S. in my case stands for Mostly Sketchy." He proposed that general imbecility might be reduced if people had to renew their diplomas the way they had to renew driver's licenses. "It wouldn't make anybody smarter. But it might slow the nonsense glut."
Not even Mr. Scott's cynicism checked my new rhythm. For events, I turned with increasing frequency to breakthroughs in science. The Question Board tracked an influx of interest in patented life. An anonymous submission of a simple penny-flipping brain teaser launched me into an aside on evolutionary statistics. A question about regional dialect differences between sodas, tonics, floats, milk shakes, frappes, jimmies, and sprinkles led me into linguistic drift and a sketch of the Sapir/Whorf hypothesis that regional word-tools predispose ways of thought.
I'd caught a salubrious dose of curiosity about the live-in puzzle from nothing more than meeting a man who had retreated from it. I must have been waiting for the slightest push, for when it came, I jumped. A dozen visits to the night hermitage and the human program took on conspiratorial beauty. The science of inherited characteristics was only my jumping-off metaphor, an entree into what until then had been neutral material. I felt the air of a new planet, the hint of unexpected links leading somewhere, things about to be revealed. I shed the curatorial, began to sense the impenetrable mechanism of mystery. Plainly put, when I woke up each morning, I knew where I wanted to be.
I had no idea whether my enthusiasm for their company was returned any way but politely. I only knew that when I visited MOL, in the presence of those two, I discovered my own powers of talk, undetected all these years. Real work was still in front of me. I had been only been resting, gathering strength for an act of connection about to become clear.
The rush of anticipation of those days lent even the most prosaic routine an edge I had forgotten. My exhilaration began to overstep propriety, at least by librarian's standards. In answering a three-by-five barely able to mask its terror about whether "secular humanism" wasn't a textbook-poisoning of the six-day wonder, I summarized the Supreme Court majority opinion, followed with Religio Medici, the Doctor's religion, and wound up with Haldane: asked what his work in life science had taught him about God, he'd replied that the Creator showed an inordinate fondness for beetles.
I received a formal reprimand. Unable to take the matter seriously, I replied that my answer contained no intended cheek. I was notified by committee that nihilism was out of line. I couldn't believe my ears. Haldane's beetle sass, so far from the opposite of nihilism, reveled in the force and grandeur of accidental creation, a creation following rules more remarkable than we ever assigned any Maker. The incident blew over, leaving invisible scar tissue; the hurt of misconstrual left me a little more eager for that somewhere else that MOL began to open up for me.
Within a few weeks I became a fixture in the deserted office suite. In the first throes of addiction, I saw that converted warehouse as the last endangered habitat left in my part of the world. Magic visits left me impatient when I wasn't there. And when I was, the lost digital domain filled me with anticipation. Something was at last about to happen. Something not in the least expected.
Inexplicable: how a room of indifferently calculating machines and two men on the beau geste shift keeping watch over nocturnal computations could stir in me anticipation profound enough to derail a life that had worked comfortably for years. I didn't know what reservoir they tapped in me, what primitive string vibrated in sympathetic resonance. And I didn't care to know.
There was the obvious explanation, of course. But an objective female jury would waffle between Todd and Tuckwell for raw desirability. Todd had the undeniable advantage of being new: his hair fell an unusual way across his temples, and I could watch for hours while his eyes modulated. Even level-headed women are programmed to spread themselves through every available backwater of the gene pool. At thirty, though, lust is no longer the giddy-maker it once was. Hormones will have the upper hand over me until their manufacture stops. But Todd's appeal — the reason I began to watch the library clock — was something else as well. From the moment I arrived at the MOL intercom to be buzzed in, he would pay steady flirtation. "What did we answer today? Wait, let me guess: the name for the plastic end-seals on shoe laces. No, no: how many wheelbarrows of Weimar marks it took to buy a loaf of bread." Tuckwell's manic humor made me laugh out loud. Todd's jokes, always sotto voce, made me ache with wanting.