“How many cell generations, Doc? And why does cell division have to stop at all?”
The old man looked longingly at the backgammon board on his chairside taboret. “About fifty cell generations in human beings. You’d know more about vegetables than I do. As to why they eventually lose the ability to function and replace themselves, there are different theories.”
Bram leaned forward in an attitude of extreme interest, chin on knuckles, elbows on knees. “Like what?”
Doc Pol sighed. “One of them is the accumulation of errors. Do you know what collagen is?”
“A large protein molecule. Chief constituent of connective tissue.”
“It accounts for about thirty percent of all the protein in the body. It supports the skin, separates the spinal disks, and so forth. Because the molecules are long, cross-links tend to form over a period of time. The tissue hardens, loses its elasticity. For a long time, Original Man thought collagen was the key to aging, simply because the effects of cross-linking were so pervasive. Wrinkles, stiff joints, slipped disks, degenerative circulatory conditions, arthritis — the lot! He worked on it for centuries and gave us the results. Now we know how to dissolve the cross-links, and that’s why, when you’re about a third as old as I am, you’ll start to go in once or twice a year for your rejuvenation treatments.” He chortled at Bram. “I passed my sevenscore and ten a long time ago — I won’t say how long, but I’m a lot closer to two hundred than I am to one hundred and fifty, and with any luck I’ll get there! And I’ll tell you this. I look a lot better and feel a lot better than youngsters of ninety did back in the days when Original Man was at the mercy of nature.”
“But,” Bram prompted delicately, “the human life span still is limited. Even with rejuvenation treatments.”
“Yes, yes,” Doc Pol said vaguely. “What was I saying? Ah! The accumulation of errors. If collagen is subject to cross-linking, so must other long molecules be. Like DNA. You’re a genetic engineer. You can imagine what that does.”
“Codons attached at the wrong sites! Inappropriate palindromes! Loops and detours! Wrong enzymes being made, or enzymes not being made at all! That must be it! Suppose you could find some way to tell those codons that they’ve grabbed a wrong place on a strand — get them to let go and cast about till they hook into an appropriate site? Like what you do in genetic engineering when you fool a stretch of nucleotide into accepting a foreign plasmid. Only in reverse! Dissolve a bond to undo the damage!”
“’Fraid not, son. Cross-linked DNA is part of the explanation, maybe, but it’s not the whole story.”
Bram exhaled. “What, then?”
“You know that DNA has a great capacity to repair itself.”
“Yes, otherwise the stray damage caused by ionizing radiation would begin to add up in a long-lived species …” He looked at Doc with new surmise. “Accumulated errors!”
“The ability of DNA to repair itself decreases with each cell generation. By the fiftieth generation it’s about gone. You know how redundant DNA is.”
“Yes. A given cell uses less than one percent of the information in its DNA during its lifetime.”
“Consider the redundant genes to be replacement parts. If a functional gene is damaged, a spare takes over its job. Over a period of time, all the spares are finally used up.”
Bram’s face fell. “That would mean there’s no hope of reversing the aging process.”
“There’s one more theory.”
“Which is?”
Doc Pol raised a sere hand and held it in front of his face as if studying it. After a bit, he put it back in his lap. “That our cells contain aging genes, just as they contain genes that mediate the various stages of embryonic and adolescent development. A sort of death switch, if you will. These switches tell the cell when the show’s over and it’s time to shut down. And there’s no cure for that, either, son. It would mean that the sequential shutdowns of age and death are just part of the normal biological process, like the genetic programming that shuts down various stages of embryonic development when the time comes. I’m told there was once a creature, called the salmon, that aged and died after spawning, but we’ve got an example closer to home — the Nar.” He shook his head. “No, my boy, if you’re looking for eternal life you’d have to imagine something that stops an inherent developmental process and keeps particular genes that are a part of our genetic material from expressing themselves.”
“Like the dragonfly does,” Bram said, half to himself.
“What’s that, my boy?”
“Nothing,” Bram said quickly. “I was thinking about heterochronic eggs. The Nar interfered with normal embryonic development there and came up with a single giant cell that absorbs nourishment through an outer membrane and divides when it gets big enough.”
Doc Pol looked at him shrewdly. “And you think genetic tinkering might some day interfere with death genes? That day’s a long way off, my young friend. Original Man never managed the trick, even at the top of his form, and we’re very small potatoes compared to him. And the Nar, even though they use something corresponding to DNA, never did it for themselves. I’ll grant you, of course, the fact that for the Nar to go chasing after immortality would be to flout a biological imperative that’s stronger than the sex urge is for us — given the fact that they can mate only once, like a flower going to seed.”
“Yes,” Bram said. “I suppose you’re right.”
“I’d rather be told I’m wrong,” the old man said. His expression became sly. “Care for a game of backgammon?”
“I’m not sure I —”
“Nothing to it. I can refresh your memory about the rules as we go along.”
Doc Pol began briskly to set out the board and pieces. With a sigh, Bram gave in to the inevitable. It was a cheap way to pay for the information he’d gotten from Doc.
Halfway through the first game, the steward sought Brain out in the common room to remind him that the second serving was about to begin. “Torm said you’d be staying for supper,” he said.
Doc Pol snapped peevishly, “Bring him a tray! He can eat while he’s playing. He’s having too much fun to stop.”
A new individual was in charge of stores — a young Nar who knew only a few words of Inglex. Patiently, Bram explained in the Small Language and with some creative boneless gestures what he wanted.
“I’ll need a container of uranyl acetate for negative staining and some standard head and tail proteins from the multipurpose insertion provirus. And an amino acid kit and some clay substrates — oh, yes, and I’ll want to check out one of the small protein synthesizers for a few days.”
Sweat broke out on his brow as he waited for the stores clerk to question him, but the slender being merely gave the perfunctory triple unzipping of tentacle edges that was a Nar nod and went soundlessly prowling through the honeycomb spaces of the supply room.
After the clerk had helped him load everything onto the carrystraps and shelves of the three-legged walker that he had borrowed for the purpose, Bram asked casually, “And would you book me some hours on the muon scope?”
The Nar clerk checked a touch list tacked to the wall. “The schedule is filled for the remainder of this quint, but if it is important to a project of Voth-shr-voth, I can get authorization from him to rearrange viewtime.”
“No, don’t bother,” Bram said hastily. “Can you just book me for next Tenday morning?”
“No one will be there to assist you then. Shall I arrange for a technician?”
“No, don’t do that. I don’t want to put anyone to any trouble. I know how to operate the equipment myself.”
He gave the walker a kick to get it started, and the synthetic resilin protein that was its motive power unsnapped and got the tripod legs going in syncopated rhythm. A walker wasn’t alive, strictly speaking — it couldn’t feel the pain of a kick, didn’t take nourishment, and merely went on dispensing the mechanical energy it could store in its fibers until one day it w
ore out.
With one hand, he guided it through the corridors, nudging it up to a walking speed just short of a pace that would attract attention, and halted it in a small cul-de-sac outside the septum where he worked. Some unused furniture had been temporarily dumped here, and an unattended walker was not likely to be noticed.
Bram draped the upper tiers of the biodevice with a tarpaulin he had brought for the purpose, then went back to his department and plunged into the work he was supposed to be doing. Today he was screening gene libraries for one of the junior subgroups. The job involved using synthetic oligonucleotide probes to trace amino acid sequences of proteins, and Bram was able to sneak in a few side searches of his own.
He waited until past quitting time, when he wasn’t likely to bump into anyone who knew him, and returned to the storage alcove. The walker was still there, its tarpaulin undisturbed. Bram triggered the elastic tendons again and got the draped biomachine into an elevator and out into the street.
He was halfway to the hackstand at the crossing when the walker quit on him. He gave it a push; it staggered on a few steps and quit again.
With a nervous glance around him, Bram dropped to one knee and felt under the skirts of the tarpaulin for the tripod legs. The bunched artificial muscles had gone completely flabby. Bram cursed himself for not having made sure the walker was fully wound up before borrowing it; a simple few minutes with a high-speed mechanical flexor would have done it.
He massaged the reselin bundles manually until he felt them knotting up, keeping a jittery eye on the incurious crowds flowing past. The sight of a human using a walker to move his possessions was not that unusual; what Bram was afraid of was that some helpful soul from the nearby biocenter would come along and get a look under the tarp. A protein synthesizer was not something that one generally borrowed.
He nursed the Walker along for a dozen yards before it came to a halt again, then had to stop twice more to massage it before he could coax it to the transport post. He hired a small pentabeast with a palanquin, heaved the walker aboard when its legs gave out again at the last moment, and high-legged it for home.
Kerthin was not there. She was out almost every night now, going to her secret meetings. She hardly bothered to keep up a pretense any longer; once Eena had come to call for her, and the two of them had gone off together after some unconvincing light conversation and an evasive exchange of glances.
She and her disgruntled friends were up to something; Bram was sure of it. What it might be, he could not guess. Some event was on the way; that was all he could surmise. Kerthin showed a suppressed excitement these days, an excitement that mounted Tenday by Tenday. Bram dated the change in Kerthin from the visit to the orbiting tree, when she had covered up for Pite, and that had been months ago. Now Kerthin kept putting him off whenever he tried to talk about a welding ceremony or a return visit to the gene co-op. She would only tell him, with an impatient toss of her head, that she needed more time to think about things, that she didn’t want to make any long-range plans before Yearsend — as if she had some hidden agenda in her mind.
Bram could hardly complain. He was keeping secrets from Kerthin, too.
In fact, he thought as he steered the lurching walker into the little spare chamber where he worked at home, Kerthin’s absence tonight had been a relief, in a way. It saved explaining. And, he thought guiltily, her frequent absences would make it a lot easier for him to do what he had to do.
To manufacture an immortality virus — even with the active cooperation of the Nar hierarchy, if he dared seek it — would be a long and elaborate enterprise. It would take a lot of manpower and a lot of Narpower, and it would require the full resources of the biocenter. It was not something to be done by one man in secret.
But he had to make a start somewhere. He could begin work on the outer structure of that tantalizing icosahedral capsid — the protein overcoat worn by the carrier virus.
Even there, Bram knew, he could proceed so far and no farther without medical accomplices and human volunteers. But he would face that problem later.
With a sigh, Bram began unloading the walker. He got out the amino acid kit and unpacked the clay substrates. For the moment, at least, he could begin the tedious job of assembling proteins.
It was after middark before Kerthin got back. She stood in the elliptical opening to the small chamber and looked suspiciously at the run-down walker and the equipment Bram had set up. “What’s all that stuff?” she said.
“Oh, just some things I brought home,” he said. “There are a few ideas I want to try out. Where’ve you been?”
She avoided the question. “That doesn’t look like the kind of thing you just bring home,” she said with a nod toward the synthesizer. “What does it do?”
“It puts chemicals together in different combinations,” he told her.
She came farther into the chamber. Her face was flushed, he noticed. She had come home with a flushed face on quite a few occasions recently, as though she were living at a stepped-up pace on her nights out.
“Bram,” she said, moving closer.
He turned the synthesizer off and stood up. He grabbed her by one wrist and pulled her to him. She melted against him. Her body felt hot and feverish, full of untapped excitement that he was expected to relieve. She had been keyed up by something tonight.
Later, lying in the nest together, there was a languid ease between them that had been absent for some time. Bram was almost tempted to bring up the subject of the gene co-op again but was afraid it would spoil the moment.
“Wouldn’t it be nice,” Kerthin sighed, “if we could stop time whenever we wanted and lie here like this and not worry about anything?”
“Hmmm,” Bram agreed. Then, reasonably, “That’s what we’re doing.”
“But then the world always comes into it again.” She propped herself on one elbow and looked at him gravely. “I mean, what if we could just float away and start all over again in a perfect world?”
“This one isn’t so bad sometimes,” Bram said lazily.
“You’re too easily satisfied.”
“Not that easily,” he said, reaching for her.
She wriggled away. “In a world that was run properly, you’d be a very important person. In a world like this, it’s the Willum-frth-willums that get the credit for everything. When you know a thousand times more about bio-crafting than he does.”
“You’re flattering me.”
“Maybe you need flattering.”
“What does that mean?”
“It means you can’t go on drifting through life. Sometimes you have to make choices.”
“I make choices all the time,” he said lightly. “I do it every time I flush a cloning tray down the drain or decide to pass it on to the biocrafting department.”
“For them to take the credit,” she said.
“That’s not the way it works,” he said uncomfortably. “Biocrafting’s a big enterprise. Everybody does their share.”
“What’s that stuff you took home with you?”
Disconcerted, he said, “I told you, I just want to work out a few ideas.”
“Why can’t you do it at the biocenter? Why don’t you want the Nar to know what you’re up to?”
“Kerthin …”
She laughed. “Never mind. It’s good to know you’re showing some spunk.” She rolled partway over to peer at him. “It has something to do with that dragonfly thing, doesn’t it?”
Bram froze. “What makes you think that?” he asked carefully.
“Keep your secrets for now, my poor, transparent love. When the time comes, you can share them with those who’ll know how to use them properly.”
“Like Pite?” he said, and instantly regretted it.
She patted his hand. “You’re very nice, and you’ll be nicer when you wake up. You need somebody to take you in hand. As Penser says, ‘discipline is better than consensus.’”
The Penser quote depressed Bram. “Kert
hin, I don’t want you talking to any of those people about what I do.”
“Of course not.”
“Don’t humor me. I mean it.”
“Could you make those dragonfly things with that equipment you’ve got?” she asked, tracing a circle on his chest with her finger.
“Is that what you think?” he said, then checked himself. “Look, you don’t understand what I’ve been saying. To craft any living organism above the level of a virus is an enormous enterprise that requires lots of different specialists. Synthesizing the DNA is only the start of the job. Then you’ve got to assemble a working cell. Even the simplest bacterium has over a thousand ‘small’ molecules — sugars, amino acids, fatty acids — and another thousand or two thousand macromolecules — the different proteins and other polymeric chains — that are hundreds of times more complex than the subunits. You’ve got to have a functioning cell membrane and, once you get beyond bacteria, a structured nucleus that’s separated from the cytoplasm. The precise three-dimensional configurations are important — the polypeptide chains have to fold up to form the properly shaped catalytic cavities. Oh, why go on?”
“Poor Bram, now you’re all upset.”
“Biocrafting is the science of life, not a weapon in some imaginary battle.”
“Never mind, Bram, sweet. Go to sleep.”
She turned over and curled up with her back to him. Bram tried to sleep, but he couldn’t.
It was a couple of Tendays later. Bram no longer worked late at the biocenter, except for those nights when he was able to gain access to the facilities of the library annex. instead, he hurried home to solve protein chains.
He was getting nowhere. It was not a job for the empirical approach. What he needed was a high-powered computer search program. Eventually, he knew, he would have to enlist a hacker — to kindle somehow the feverish monomania that those strange involute creatures thrived on while concealing the true purpose of the program. In the meantime, he plugged away, gaining experience that might translate into a more successful search technique.
The Genesis Quest Page 20