The Yarbat AG arrays built into the Aztec's deck structures were working well. They made the whole ship more compact and elegant of line than the ungainly, rotating conglomerations of struts, booms, tethers, and ties that had been gyrating around the Solar System since before Kronia was founded. It was more in keeping with what unaided imagination and intuition thought a spacecraft should look like. Vicki saw it as the beginning of a revolutionary technological era, like those that had brought steamships, trains, automobiles, airliners. And there had been no complaints of the vertigo that affected some people in the older vessels.
She sat in one of the workstation booths provided for personal use, making notes from the latest transmissions from Charlie Hu and Pieter Naarmegen on Earth concerning their biological and geological findings, with comments contributed by Emil Farzhin's group back on Dione. There seemed no escaping the conclusion that the genetic codes that enabled such rapid adaptation to occur had to be present already in the genome. And as already postulated, the most likely mechanism for getting them there, and propagating them quickly through a population, was infection. In itself, however, simply admitting foreign genetic information into cells somewhere in the body wasn't enough. To become a fixed trait in a species, it would have to somehow find its way to the reproductive cells and there be incorporated into the germ DNA to be transmissible to subsequent generations. Farzhin had put forward the suggestion that in fact a mechanism of precisely this nature had been known for a long time, which Terran science had read as reactions to a new class of virus.
It sometimes happened that strong environmental pressures caused cells to begin manufacturing certain proteins on a modest scale, but not a high enough rate to disrupt the cell's normal functioningunlike "real" pathogenic viruses that caused sickness by killing cells. These packages then budded off through the cell membrane wrapped in a blanket of host proteinthe ideal camouflage for navigating the hazards of a hostile immune systemand on arrival at the germ cells were written "backward" into the DNA there by the reverse transcriptase enzyme, tailor-made for the purpose, but whose reason for existence had been baffling researchers since the previous century. In short, Farzhin maintained, the messenger proteins that were the products of some sickness conditions that had been read instead as antibodies to nonexistent viruses. In other words, results were taken to be causes.
The suggestion that alterations to the genome could be triggered by forces in the environment rather than coming about purely through chance flew in the face of what had been unquestionable biological dogmaif not smacking of open Lamarckism, then running perilously close to it. But that was of little consequence to the Kronians, who had seen too many of Earth's once-sacred doctrines come apart in any case.
One of Vicki's favorite examples was the mutations in some strains of bacteria that confer a resistence to mycin antibioticsat one time widely acclaimed as demonstrating "evolution in action." Of course, the theory had never held that individuals evolve. A cat lives its life and dies with the same genetic endowment that it was born with. What was believed to evolve with the passage of timeeither gradually, or in jumps, or howeverand get passed down from generation to generation was the accumulating information that makes up the genome. The form exhibited by a species was seen as snapshot of that information expressing itself at the point reached at the time in question. On average, therefore, every meaningful step along the way added some finite amount of information to the growing genome. Or to put it another way, to be considered a meaningful contribution to the evolutionary process, a mutation would have to add genetic information that hadn't been there previously.
But every point mutation that had been studied by generations of researchers turned out to have reduced genetic information, not increased it. In the case of antibiotic resistance, the mutations responsible acted in such a way as to lose the specific shape of the docking site on the bacterial ribosome that enabled a molecule of the drug to attach itself there and render the bacterium dysfunctional. The information was lost that was needed to make the fit a precise one. Hence, "evolution in action" turned out to be nothing that could be construed as contributing to the process at all. As in business, where you can't accumulate money by losing it all the time.
Wherever it came from, adaptive genetic information seemed to be already there, in the genome, waiting for cues from the outside to activate it. In another example that Vicki had studied, experimenters had bred a deficient strain of bacteria that normally live on the milk sugar lactose, lacking in the enzymes necessary to metabolize it. But if two particular mutations happened to occur together, they would operate in conjunction to create a path by which an alternative sugar could be metabolized instead. According to calculation, it should have taken about a hundred thousand years for one of the double mutations to occur. In fact, over 40 instances were observed within a few days. But this happened only when the alternative sugar was present in the culture. Somehow, the presence of the needed nutrient was triggering the mutations necessary for it to be utilized. This and many other examples like it had been known long before the Athena catastrophe hit Earth, but they had provoked such outrage and controversy among defenders of the faith as to be denied or ignored.
"Luthis tells me it's all coming together," a voice remarked nearby. Vicki had been too engrossed to notice that Wernstecki had stopped by the booth and was looking in. His gaunt features with their intense eyes and pointy nose beneath his shock of frizzy hair did their best to approximate a smile. "He says Farzhin is firing out one theory after another."
Vicki leaned back in the chair and rubbed her eyes. "And some of the things they're finding on Earth look as if they might be bearing it out already. We're heading for some exciting times, Jan. A complete rewrite of the script. It all happened more recently and faster."
Wernstecki cast an eye quizzically over the screens and notes that Vicki had been working with. Such things were not his specialty, and he didn't pretend to any great knowledge of them. "But doesn't it mean that the whole geological time scale would have to be rewritten too? That's the thing I wonder about when I hear all this."
"Pretty drastically," Vicki agreed.
"I thought it was supposed to have been validated over and over."
"You mean by things like radio-dating?"
"Yes."
Vicki took a moment to save some items on a screen before answering. "That used to bother me once too," she said. "Oh, the theory is solid enoughconvert one isotope into another at a known rate, and the ratio will tell you how long it's been going on. But when you get down to the actuality, you run into the problem of contaminants acting to add to or subtract from either or both. That can produce some very different answers. One of the worst can be water, which gets just about everywhere."
"I thought they made corrections for things like that," Wernstecki said.
"But to figure out the corrections, you have to know what the right answer is. And that's where the whole thing got circular. The picture of immense time scales was put together with theories of slow, gradual change already in mind. Radiometric methods came later, and were used to 'confirm' what was already 'known.' "
"The agreements were selected?"
Vicki nodded. "The normal practice was to ask someone submitting a sample the range that was expected. Anything falling too far outside it was rejected as bad data. What was left obviously fitted the theory, and so of course it all held together." Vicki smiled at the expression on Wernstecki's face. "And then you had the assumption that the initial mix of isotopes in the environment hadn't changed. But who knows what changes things like this last incident made in Earth's atmosphere and oceans? That's one of the things the Varuna and the Surya are measuring." Vicki concluded, "Anyway, Jan, talk to Luthis. He knows more about it than I do."
"I will, when I get a chance." Wernstecki changed the subject by jumping lightly on the floor outside the booth. "Like them?" he asked.
"The AG arrays? I was just thinking before you arrived, it'll change the look of ships forever. No more whirligigs and flying umbrellas. How are they shaping up technically?"
"Not many snags at all so far. We'll see how it goes with the heavy-power, rock-cutting stuff when we get to Earth."
"Lan's department," Vicki said.
"Heard from him lately?"
"Not since they found more survivors." The discovery of migrants in western Asia had been big news aboard the Aztec, and presumably back in Kronia. There were unconfirmed claims of other sightings too.
"So it seems that all the people who thought that going back now was premature were wrong," Wernstecki said. "We're just arriving in time to make a real difference."
"Lan thinks so too," Vicki said. She was about to add more, when a message window opened on one of the screens to show the face of Commander Reese, the Aztec's skipper, calling from the Bridge.
"Ms. Delucey."
"Yes?"
"Ahem . . . I wonder if you could come to the Bridge, please."
"Well, yes . . ." Reese's grave expression and tone of voice registered then. "What is it?" Vicki asked.
"There is something I have to tell you. I'd rather it were done face to face, personally."
Vicki swallowed, feeling her mouth go dry. "Very well," she managed. "I'll be there right away." She cut the connection.
"Want me to come along?" Wernstecki asked. "I was heading that way."
"Sure," she said automatically, her mind racing through a score of possibilities.
They arrived less than five minutes later to find Reese waiting outside his working stateroom. "I think this should concern you alone," he told Vicki.
"I'll wait here," Wernstecki told her.
Reese ushered Vicki into the stateroom, which was otherwise unoccupied, closed the door, and indicated for her to sit down. Then he looked at her. "You have a son with the Trojan expedition, heading for Jupiter, I understand," he said.
Something tight convulsed in Vicki's stomach. "What's happened?" she whispered.
Reese made an empty-handed gesture, as if to say there was no other way to put this. "We've just received word from Saturn that all contact with the ship has been lost," he said.
A message of sympathy came in from Emil Farzhin and the others in the Academy on Dione not long afterward. Almost two hours later, because of the longer delay times, communications expressing similar sentiments arrived from Keene, Sariena, Charlie Hu, and Gallian on Earth. All of them urged her not to give up hope just yet. But beyond that, there was little anyone could say. It was a time of danger and perils all over the Solar System.