Dark Ararat - Brian Stableford [47]
Lityansky understood that, but he had his own order of priorities. He insisted on “putting the information in context,” perhaps because he thought it necessary and perhaps because he wanted to inflict a little subtle punishment on Matthew for screwing up his schedule.
“You might have heard mention of a life-bearing orphan planet that we passed close by two hundred years ago,” the biologist said. “We’ve had reports from Earth’s robot probes of two others, and of half a dozen life-bearing planets in solar systems closer to Earth than this one. That knowledge had already informed our grandfathers, long before we arrived here, that the panspermists and the more extreme convergence theorists were wrong. DNA isn’t the only basis of life to be found in the galaxy, and doesn’t appear to be common. Perhaps one coding molecule will eventually win the cosmic struggle for existence by out-competing all its rivals, but that certainly won’t happen soon—and by soon I mean any time in the next few billion years. Everything we have so far discovered suggests that we live in a galaxy in which life is very various.”
“But most of the rivals to DNA you’ve so far discovered,” Matthew put in, “aren’t capable of producing anything but bacterial sludge.”
“We don’t know that,” Lityansky said. “DNA probably couldn’t produce anything but bacterial sludge in the context of an orphan planet, and we’ve no reason to think that any of the alternative coding molecules present on such worlds would be incapable of producing complex life if they had the resources of a sunlit planet like Earth or Ararat to work with. It might, of course, be unreasonably arrogant of us to think of such worlds as the primary abodes of life or as the highest achievements of evolution. It is at least conceivable that one of the many kinds of bacterial sludge that exist in less balmy conditions will ultimately out-compete everything else, proving that metazoan creatures—including sentient humanoids—are merely temporary follies of creation.”
“Fair enough,” Matthew said. “So tell me about temporary folly number two.”
“I think you’ll find it intriguing,” Lityansky told him, teasingly. “Until we arrived here, everything we had learned from our own orphan and the data harvested from Earth’s probes suggested that there was one candidate rule of comparative evolution that seemed to have held firm. In all the other cases known to us, each ecosphere had only one fundamental reproductive molecule—DNA and RNA aren’t sufficiently different, of course, to be reckoned fundamentally different. The coding molecules were all different, but each ecosphere was derived from a single biochemical ancestor. Earth is now a partial exception to the rule—the news from home says that Earthly biotech has been enhanced by a whole new range of artificial genomic systems based on a molecule whose primary version was dubbed para-DNA—but that was the result of clever artifice. Ararat is a genuine exception: a natural exception.
“The inference we had taken from the fact that each new ecosphere had only one fundamental coder-replicator was that in any limited arena, one reproductive molecule would be bound to win out over all others in a primordial competition—a biochemical variant of that discredited pillar of primal ecology, Gause’s axiom. That axiom can now be discounted at the biochemical level as well as the specific level. Here on Ararat there are two fundamental reproductive molecules, whose competition has been resolved in a rather peculiar way.”
“Go on,” Matthew