Kojo Suzuki - Spiral

This might work, he thought.

But just as he was about to get to work, he stopped. He could see where this was going, too. If he not only had to decide what letters each triplet stood for, but also had to figure out how to rearrange the letters, the task suddenly became a mammoth one. And it wasn’t just a question of time. Without a key of some sort, he’d end up with the same sort of problem he had run into earlier: a plethora of possible solutions with no way to choose among them. He thought of the numbers that had led him to “ring” and wondered if they might somehow be that key, pointing him toward the right order in which to arrange the letters now. But first he’d have to figure out what letters the triplets stood for.

Another dead end.

You need a fresh angle on this, Ando told himself. He was trying to proceed by trial and error, but he felt like he was just trying the same thing over and over. Maybe he was too fixated on the idea of making each set of two or three bases correspond to one English letter.

The solution has to be something unambiguous, something that I can figure out without going through a long, complicated process.

He felt his concentration faltering, his eyes wandering away from the page. He suddenly realized he was staring at the hair of a young woman seated at the other end of the same table. With her head down like that, she looked like Mai Takano, especially her forehead.

Where is she now?

He worried about her safety, especially when he considered that she used to be Ryuji’s lover.

Could Ryuji be trying to tell me where she is with this code?

He considered the possibility for a moment, but then discarded it with a derisive laugh as being too comic-book. How adolescent, to imagine himself as the famous detective out to save the heroine from mortal danger. Suddenly the whole thing seemed foolish to Ando. This probably wasn’t a code at all. There was probably a perfectly scientific explanation for how that sequence of bases got into the virus’s DNA. And once Ando admitted that possibility, he could feel his passion for code-breaking vanish. He was just killing time anyway, right? He was working awfully hard at it.

The setting sun was turning the hairs on his upper arm golden. All the intensity he’d had that morning was gone now. He thought about moving to another seat, where the sun didn’t hit him, and started to get up. Looking around, though, he saw he was surrounded by kids, college students or high school kids studying for entrance exams, all dozing behind mountains of books. Moving wouldn’t help him get his concentration back. The entire reading room was enveloped in drowsiness. Ando sat back down where he was.

Think about it logically, he told himself. There has to be a formula.

He sat up straight. He’d been trying to assign letters of the alphabet to trios of bases, but that didn’t work out to a formula. If he could get it down to a one-to-one function, or even a several-to-one function, then the answer would become obvious. One-to-one, perhaps several-to-one… There had to be a formula like that to be discovered.

He stood up. Logically speaking, there was no other way. His intuition told him that he’d moved one step closer to a solution, and the realization blew away his torpor, spurring him to action.

He went to the natural sciences section, found a book on DNA, and started flipping madly through the pages. As his excitement mounted, his palms grew sweaty. What he was looking for was a chart that gave what amino acid each trio of bases formed.

Eventually he found one. He took the book back to his table and laid it out flat, opened to the chart, next to the coded message.

When a trio of bases, a codon, forms a protein, the codon is translated into an amino acid. The principles by which the translation takes place were contained in the chart Ando had found. There are twenty varieties of amino acid. There are four bases, meaning there are sixty-four separate combinations of three that can be formed. With sixty-four combinations standing for only twenty amino acids, it meant there was quite a bit of overlap. It was several-to-one mapping. Each trio of bases signified one amino acid or another (or a stop).

Consulting the chart, Ando wrote the abbreviated names of the amino acids below the forty-two bases of the code.

Next he took the first letter of the name of each acid and lined them up:

MGGGTATIPPPGGG

But this meant nothing. And he was still faced with triple letter combinations. It seemed he’d have to figure out what to do with them no matter what. There had to be another interpretation. For example, maybe a third straight repetition of the same letter meant that the first two should be interpreted as a space between words.

He tried that:

MG TATIP G

That wasn’t English either.

But all the same, Ando felt he was getting somewhere. He could tell he was closing in on the solution. He didn’t know why, but he felt that any minute now he’d come up with a word that made sense.

Met, Pro, and Gin were the ones that were repeated three times. He tried writing them out a different way:

He stared at this list for about a minute, and then he saw an English word he knew.

It occurred to him that the codons repeated three times might signify not “three” but “third”. As in, the third letter of the abbreviation for the amino acid.

In other words:

Which meant the solution was: Mutation.

Forgetting where he was, Ando let out a groan. The only answer he’d been able to come up with, as a result of logic, method, and trial and error, was this. It was a simple, clear answer, and it had to be right.

But still he had to hang his head. He knew the meaning of the English word “mutation”-that is, he knew what it meant in an evolutionary biological sense. But he had absolutely no idea how he was supposed to take it in this context.

Just what the hell are you trying to say, Ryuji? He didn’t speak the question aloud. But even in his own head, Ando could hear his voice tremble with excitement at having decoded the message.

He went to the hall, found a pay phone, and dialed Miyashita’s number. He doubted his friend would be in, given it was a Saturday evening in the middle of a three-day weekend, but lo and behold, Miyashita was at home with his family. Ando was able to tell him that he thought he’d deciphered the code.

Ando figured Miyashita was probably in his living/dining room; in fact, he could practically see Miyashita’s wife and children getting ready for dinner. Miyashita himself was cupping a hand around the mouthpiece to keep out the background noise but was unable to keep his halcyon home life from filtering through.

“Good show! That’s excellent. What did it say?”

Miyashita had a loud voice to begin with, and with his hand cupped around the mouthpiece it rang even louder in Ando’s ears.

“Well, it wasn’t a sentence. It was just a single word.”

“Okay, so it was only one word. What was it?”

“Mutation.”

“Mutation?” Miyashita repeated the word several times, as if trying it on for size.