Inherit the Earth - Brian Stableford [44]
Damon had given up genetics ten years before and had carefully set aside much of what his foster parents had tried so assiduously to teach him, but he understood the implications of what Kachellek was saying. “Is it new,” he asked, “or just something we managed to overlook during the last couple of centuries?”
“We can’t be absolutely certain,” Karol admitted scrupulously. “But we’re reasonably certain that it wasn’t here before. It’s a recent arrival in the littoral zone, and as of today it hasn’t been reported anywhere outside these islands.”
Damon wondered whether as of today meant that Karol had reason to expect a new report tomorrow or the day after, perhaps when the mud samples he’d loaded onto the lorry had been sieved and sorted. “So where did it come from?” he asked.
“We don’t know yet. The obvious contenders are up, down. . . .” The blond man seemed to be on the point of adding a third alternative, but he didn’t; instead he went on: “I’m looking downward; Eveline’s investigating the other direction.”
Damon knew that he was expected to rise to the challenge and follow the line of argument. The Kite had been dredging mud from the ocean bed, and Eveline Hywood was in the L-5 space colony. “You think it might have evolved way down in the deep trenches,” Damon said. “Maybe it’s been there all along, ever since DNA itself evolved—or maybe not. Perhaps it started off in one of those bizarre enclaves that surround the black smokers where the tectonic plates are pulling apart and has only just begun expanding its territory, the way DNA did a couple of billion years ago—or maybe it was our deep-sea probes that brought it out and gave it the vital shove.
“On the other hand, maybe it drifted into local space from elsewhere in the universe, the way the panspermists think that all life gets to planetary surfaces. We have probes out there too, don’t we—little spaceships patiently trawling for Arrhenius spores and stirring things up as they go. Maybe it’s been in the system for a long, long time, or maybe it arrived the day before yesterday . . . in which case, there might be more to come, and soon. I can see why you’re interested. How different from DNA is its replicatory system?”
“We’re still trying to confirm a formula,” Karol told him. “We’ve slipped into the habit of calling it para-DNA, but it’s a lousy name because it implies that it’s a near chemical relative, and it’s not. It coils like DNA—it’s definitely a double helix of some kind—but its subunits are quite different. It seems highly unlikely that the two coding chemistries have a common ancestor, even at the most fundamental level of carbon-chain evolution. It’s almost certainly a separate creation.
“That’s not so surprising; whenever and wherever life first evolved there would surely have been several competing systems, and there’s no reason to suppose that one of them would prove superior in every conceivable environment. The hot vents down in the ocean depths are a different world. Life down there is chemosynthetic and thermosynthetic rather than photosynthetic. Maybe there was always room down there for more than one chemistry of life. Perhaps there are other kinds still down there. That’s what I’m trying to find out. In the meantime, Eveline’s looking at dust samples brought in by probes from the outer solar system. The Oort Cloud is full of junk, and although it’s