Gene Mapper (4 page)

“You mean Barnhard?”

I had a sinking feeling. There was no way I could isolate the intruder’s DNA before tomorrow. Kurokawa would catch the heat instead of me, and he’d be hung out to dry, if not by the industry then at least by L&B.

“Yes, the one and only. It’s not that he doesn’t trust Enrico, but it was Lintz who managed to grow Mother Mekong into a five-star project. It’s getting lots of attention from all over the world. He’s worried, of course.”

“Do you need me to back you up?”

“It’s all right, Mamoru. Get a good night’s sleep and keep working on your analysis. That’s the most important thing right now.” He sighed. “I’m sorry to say this, but Lintz is becoming a problem. He really ought to leave everything to Enrico. He knows the project in much better detail. Recently Lintz has been all over every little thing …”

It was rare to see Kurokawa grope for words. His face darkened. He closed his eyes, knitted his eyebrows, and grasped his lower lip between thumb and forefinger. Suddenly he looked very young. His glasses and seemingly painted-on hair had always drawn most of my attention, but with his flawless skin and darting pupils, I realized he could easily pass for a teenager.

“I’m sure Enrico’s livid, but Lintz has taken over the investigation. At least that’s what seems to be going on. A few people have seen him chewing Enrico out over the last few hours.”

I’d heard about Barnhard’s political savvy. If he decided Enrico wasn’t making the cut, he’d not only make sure he was out, he would make sure no one in the industry remembered him after he left. Good thing I was a freelancer. We were usually insulated from corporate politics.

“If Barnhard starts stirring things up, people on the front line will lose their motivation,” said Kurokawa. “I want to prevent that by making sure he isn’t worried about the technology. I hope you can help me.”

“All right. What do you need to know?”

“Let’s keep it short. If I can explain the principle behind color mapping, and why we weren’t able to do L&B’s logo in full color, I can get over tomorrow’s hump. That’s all. Go ahead.”

“That’s all” was a lot. Where to begin? For a moment I was stumped. I had hardly understood the principles myself when I first encountered them as a polytechnic student.

“Well, let’s see. As the leaves and blossoms of distilled crops grow, color expression genes trigger development of receptors for chemical messengers—plant hormones. When the messengers are dispersed from towers in the right concentrations, color expression genes are activated and promote cell division …”

Kurokawa’s wide-eyed expression said
I don’t understand.
I didn’t get it either at first, and I had a lot more background at the time.

“Let me draw you a picture. Sorry, could I have something to write with?”

The waitress returned with a tray full of writing widgets. The tray was just a prop, another nice touch from Zucca to make you feel like a customer in a “real” café. There was a full selection, everything from quills to drawing pens. Everything links with your workspace drawing app—they’re all the same AR widget.

I chose four highlighting pens in different colors. Kurokawa leaned forward and picked up—I couldn’t believe Zucca had something so primitive—a red lead pencil.

“Draw anywhere you like. Use the tablecloth or a napkin,” said the waitress. “If you need ‘paper’ to take your work away with you, just let me know. Oh, one more thing”—she pointed to the space between me and Kurokawa—”If you write anything here, just remember you can’t print it out. Have fun!”

“Thanks. I’ll let you know when we’re done.”

She hoisted the tray onto her shoulder, winked, and walked away. I was impressed with the natural way she handled the tray, which was of course empty.

“Shall we begin? Let’s say our crop responds to only two chemical messengers, orange and green. When both messengers arrive in the right concentration, the leaves of the plant change color. With SR06, the style sheet would look like this.” I wrote a style sheet selector,
.lea
f
(orange==green),
in the air over the table. “Now let’s see how the color is expressed when the messengers arrive.”

I drew two small crosses on the tablecloth about eight inches apart. One green, one orange.

“These are the messenger towers. Mother Mekong has a few thousand, but two is enough for this example. The chemical messengers are dispersed from these towers.”

I looked up to make sure he was with me and drew a circle centered on each cross, about two inches in diameter in matching colors.

“Mamoru, what do they use for messengers?”

“Mostly leaf alcohols. Other compounds are used too, but most of the time it’s something with the same chemical structure as a natural attractor.”

“Is that to comply with the Full Organic protocol?”

“I don’t know. But if they stay natural, they don’t have to worry about nature addicts tramping around the site.”

“Do these messengers use—what are they called—optical isomers?”

This was an old term. I wasn’t sure how Kurokawa came up with it. He was talking about chiral molecules—molecules that are mirror images of each other but nonsuperposable, like left and right human hands. Some very weird effects can happen when big molecules, like sugars or proteins, are switched with their optical isomers.

“We usually just call them isomers. Where’d you get that anyway? Now that I think of it, L&B has a policy of not using them with their distilled crops. The competition stopped using them too after the fifth generation.”

“Thanks. Just wondering.”

“Let’s keep going.”

I put a fingertip to the orange circle. Handles popped up for resizing and dragging, mimicking my workspace environment. I pressed on the resizing handle and set the animation parameters. The circle started expanding.

“The tower releases a pulse of the messenger in aerosol form. It spreads out over the field.” The little circle, oscillating gently as it expanded, did a good job of replicating the way the aerosol moved out from the tower.

“Now, if we send pulses from both towers simultaneously—” I touched the orange circle to stop the animation, copied its attributes, pasted them onto the green circle, and restarted the animation. “The orange and green circles expand, and eventually they have to overlap, right?”

Kurokawa watched intently. The red pencil he’d been toying with had migrated to a perch behind one ear. That was the first time I’d ever seen someone do that with an AR widget. Zucca …

“That’s how you draw a straight line.”

“Just a second, Mamoru. Where is the line drawn?”

“Between the towers. Let’s slow down the animation and mark the intersections of the circles.”

I adjusted the controller to slow down the animation. The two circles kept expanding and finally touched at the midpoint.

“The messenger pulses join midway between the towers. The plants in this location receive both messengers at the same time. That activates the genes for color expression.”

I stopped the animation and drew a red
x
where the circles touched. Kurokawa nodded. Now he had the pencil wedged between his nose and upper lip.

I restarted the animation, and the circles began to overlap. “When the messengers are released simultaneously, color genes are activated in plants that are the same distance from both towers. As the crops change color, they draw a line right down the middle of the space.”

I ran the animation four times, adding four more marks above and below the first mark where the edges of the overlapping circles touched. Now I had nine marks lined up vertically between the towers.

“Short pulses produce narrow lines. Longer pulses—several seconds, say—produce thicker lines. In this case, two circles have drawn a single line.”

“I see. So it’s as much about controlling the environment as controlling the genetics. But …”

Kurokawa was rolling the pencil between his palms, head cocked to one side. I knew how he felt. The first time I heard this explanation, I couldn’t figure out how gene mappers made the jump from straight lines to the complicated figures being produced in the real world.

“Bear with me a bit more, Takashi. If we want a curved line, we just delay one of the messengers.”

I reset the animation, this time with the green circle starting later. The orange circle moved outward to contact the green circle a bit closer to its tower. I used the blue marker to mark the contact points. Now the plot was a curve.

Kurokawa leaned forward and started helping me, adding marks to the plot here and there, more or less at random, but accurately. He was getting the hang of it.

“All right, I understand. With only two towers, you can draw straight lines of different widths or curved lines.”

“Right. Say you add another orange tower to form an equilateral triangle. Release the messengers at the same time and you can draw right angles. Vary the timing and you can trace a variety of curved lines.”

I got to work adding more towers and circles. Soon the table was covered with overlapping waves tracing complicated patterns. Both of us were busy adding marks to the intersection points when Kurokawa said, “So far so good. I think I grasp the principle. But can you really use this to draw a logo? The towers are fixed, and the terrain is uneven. I still don’t see how you could draw complicated figures like logos and letters.”

“What I do first is build a kernel of the design with a few towers. I guess it’s easier if I show you.”

I opened my workspace and pulled a preliminary sketch from the Mother Mekong project file. Zucca’s stage rendered it as an old-style blueprint. The layout showed fifty or so towers surrounding the letters
L&B
depicted in spidery lines. The design was far from a logo—all I had at this point was the size of the design and the rendering topology. For L&B,
L
had no enclosed space, while
&
and
B
each had two enclosed spaces.

“The mapper has to specify the initial layout manually. First I create a sketch like this. Then I let the program figure out the timing needed to draw it with these towers.”

Kurokawa wrote an equation in midair above the table—an exponential function that had an astronomical number of possible solutions.

“Mamoru, with only four releases from each tower, there are several billion possible combinations. But there are a lot more than four towers. Fifty trillion combinations? No, even more. How do you derive the sequence you need?”

“Gene expression programming. You break the random patterns into ‘genes,’ score them for fit, and make them compete. As stronger genes emerge, you add system noise and keep pitting them against each other.”

“And what you’re hoping is that the release sequence to draw your logo evolves out of the noise?”

“Right. It’s not accidental. Even with only fifty towers, the search space that contains all the possible messenger release patterns is practically unlimited. The solution is to apply selection pressure to drive the process in the right direction. Different gene mappers have their own selection algorithms.”

“Interesting. Manipulate the evolution process to speed up the search. Okay, I’ve got it.” Kurokawa laid his pencil on the table and nodded. “Next question. Why couldn’t you render the logo in full color?”

“They had to limit the number of towers to get Organic Covered Certification. The whole site only has about two thousand towers. With that, I have to render two logos and five cert marks. Even L&B’s total computing capacity probably couldn’t handle all the rendering calculations, and as the logos get more complicated, butterfly effects start becoming a problem.”

“That makes sense. All right, I think we’re done. You’re an excellent teacher.”

“You’re a fast learner. I’m surprised. It took me a whole semester to wrap my head around it.”

“I’m ready for tomorrow. I owe you one. Now let’s deal with your request.”

Kurokawa took an envelope from his briefcase. As he laid it on the table, I felt a slight pressure in my throat and ears. The environment turned grainy, like old 35mm film. That, and the AR feedback I was feeling, meant Kurokawa had switched to Private Mode. Zucca’s rendering approach was beautiful. It was like being in a Technicolor movie.

The babble of voices around us faded to a soft, unintelligible drone. Private Mode in public spaces is usually dead quiet, but Zucca’s production values include background noise that sounds like people speaking Japanese. The customers were replaced by avatars instead of gray silhouettes. Zucca had a reputation to maintain.

“Mamoru, I have the Mother Mekong cultivation logs and TerraVu photos you asked for. I also asked them to collect another sample. Thep wasn’t very happy about that, but she said she’d send you DNA from a full-grown SR06 plant too, just in case.”

“Thanks, Takashi.”

Kurokawa tapped the envelope, and it morphed into a standard folder. The security scan ran, and
SCAN COMPLETE
popped up.

“They sent me the cultivation logs when they told us about the mutation. I should’ve given them to you then. Sorry about that. I thought it wasn’t necessary, so I held on to them.”

He was right. The records didn’t contain much that was helpful. Everything jibed with the reference schedule. The intruder had been discovered about ten days earlier. Until then, the crop had been expressing the logos and cert marks exactly as specified.

“I was hoping this was Mother’s mistake, but these logs look pretty professional. Lots of detail, well-organized.”

“Thep is still young, but she used to do environmental agriculture consulting out of her own lab at Nankai Institute of Technology in Singapore. She knows her stuff. Mother Mekong couldn’t have gotten all five certifications without her help.”

She knew her stuff? Two hundred gigabytes of DNA data?

“So Thep is a woman,” I said finally.

“All I needed from you was the style sheet. You didn’t need to deal with her.”

“Yeah, I was too busy coding the damn plants to glow at night.” I held up one of the TerraVu satellite shots. The L&B logo stood out black against the faintly glowing fields.