RNA World

By Felix Barber

Imagine a furnace underwater. No, not like that; I didn’t say the water leaks through. Just the heat. Just the overpowering vitality of earth’s raw fuel being spent, replaced, recycled, spent again in an engine that spews forth energy as fast as you can devour it. Let it infuse you, and you will experience the vibrations, undulations, dizzying highs and lows as the bonds defining you bend, break, reform, then break anew. My world is not the permanent one with which you count yourself acquainted; my world is impermanence. Great changes—dizzying in scope if not in size to one such as you—occur swiftly, then are reversed again equally swiftly. It is in this world that I came to be.

When I first began assembling myself, a singular carbon-oxygen ring drifting in the soupy bathtub of existence, I did not truly know what a phosphate was. What I did know, I did not care for. Phosphates are ephemeral; they lacked the elegance of my circular, pentose form, and they further lacked discretion. You should understand that I am not by my nature aloof. Even then, when I had not yet conceived of myself as an entity unto myself, I had already taken pity on an errant hydroxyl group, one I saw would soon waft from our lovely, scalding patch of ocean into the cold abyss beyond. I took this hydroxyl and I fused it to my core with what some might consider reckless abandon, and I have never once regretted it. Encouraged by such, you can perhaps appreciate that a phosphate’s eagerness to find a home became, to me, a sympathetic cause. I believe this is what led me to finally look past the phosphate’s promiscuity—an insincerity that even now I suspect is born of desperation—and bring one into the folds of myself.

Immediately, I regretted my decision. My houseguest, at first sight a singular tetrahedron, had a guest of its own tagging behind. There, blushing with its impropriety, was a diminutive mimic of my own, sugary self. As I have said, I am not aloof; nor, however, did I deem it appropriate to sully my elegant circularity with such a skewed entourage. Why, any bystander might mistake that misleading phosphate for the core around which my copy and I had assembled, like husks around corn. I know now how fortunate I am that even then, in my utmost dismay, I was denied the chance to obstruct further progress. While I grappled with my new and unwanted protrusion, another phosphate presented itself on my opposite side, while a base—one whose name I could scarcely pronounce—jostled over to me under some pretext of light conversation. Without a word spoken, both would-be suitors seized upon my confusion and bonded to me quickly, before I could deny their requests. I was being assaulted on all sides! Somehow, within roughly the same time it had taken me to consider adopting my first, humble hydroxyl, I had been sized up and seized upon by a pack of vagrants.

“But you are RNA!” I hear you cry. “Surely you must have known this augmentation to only be a good thing!”

To you, I ask, does the caterpillar know that its death brings new life? Almost certainly not, for the caterpillar knows only snippets of what is to come when its chrysalis forms and its old body slowly dissolves into a puddle of carefree proteins. The caterpillar is gambling, seeking to further its existence without bothering to understand the how or the why. But caterpillars and butterflies did not exist yet, and I was no gambler. At least, not initially.

Nothing I had experienced before then had prepared me for the heady rush of my new form. With phosphate and base, hydroxyl and yes, even my unwanted mimic adjoining me, life assumed a depth of meaning it had not previously. As unwilling as the transformation to my lengthier, weightier self had been, as much as it saddened me to have lost that cherished singularity of my youth, I soon came to appreciate life’s new fineries. For one, my capacity to interact with my fellow occupants in this churning carbon slew was greatly enhanced. My newly grafted base turned out to have friends in dizzying variety, and with my initial reservations swiftly fading, I would take full advantage. I quickly took on further additions, lengthening and shortening myself with new (though still, admittedly, distasteful) mimics according to my own desires, forcing my choice of base onto each new monomer as an overzealous clerk might quickly ram hats onto customers at a primordial hat store. It was not long before I became addicted. My desires were all encompassing, and fleeting. I would adopt a whole sequence of base pairs only to cleave them off on a whim. I would spend hours examining myself, considering the shapeliness of one motif over another, luxuriating in their touch, their feel, reveling in the splendor of choice that had been granted me.

There were, of course, others. Gaudy imitations, all. Jostling in the stew, one frequently encountered structures that, though superficially alike, had suffered from a lack of vision. Bases mindlessly repeating into the darkness—longer than I, maybe, but length has no meaning when all is alike—or phosphates and hydroxyls protruding in unnatural and unaesthetic configurations, or bland cores who never considered the advantages that a single added hydroxyl might bring, or otherwise promising strands that had inexplicably confined themselves to circularity (note how, even then, my old ways had become tedious for me).

All things have their uses; so did they. Through their deficiencies, I learned how to avoid those unsightly conformations—hairpins, tangles, voluntary or involuntary loops—brought about by thoughtlessly chosen base sequences. It was in such labors of introspection that I first made my Great Discovery.

Until then, it had seemed only a curiosity that certain bases sought the company of certain others. For myself, I saw no reason to indulge such; I would ruthlessly bat away any bases that might through their assertiveness sully my serpentine form. But persistence is the end of discipline; even the strongest wills give in eventually. So it was that one day while inspecting my shapely tail, I allowed an unfamiliar base to hydrogen bond to one of my own. I will admit, the sensation was not unpleasant (something you giants can, perhaps, relate to). But nor did it end there. As soon as that base assembled—alongside its requisite sugar and phosphate, for no good deed goes unpunished—another was ready to join it, and another after that. For reasons unknown to me, I indulged them, and my sightly form was quickly overcome by a steadily lengthening strand that was in every sense my opposite. It was hideous; it was beautiful. Within those folds, I saw myself more clearly than ever before; more clearly than any should. I convulsed, desperate to free myself from my intrusive counterpart, willing the power of our molten surrounds into each and every point of contact, feeling these points separate as giants such as you would (for you would) tear buttons from a shirt.

And then, finally, it was done.

I regarded my unwilling double in silence; they looked back in equal silence. I wondered what it meant. What manner of world was this in which one could be so readily inverted, distorted, reconstructed in form alike yet unlike? I was ready to turn away, to rid myself of the enterprise altogether, to forget.

It was only from the corner of my vision that I saw it: my dark twin, my soulless copy, inspecting its own tail. There, just as had happened so innocuously to me mere moments prior, a base was slotting neatly into place.

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