"James P. Hogan - Giants 2 - The Gentle Giants of Ganymede" - читать интересную книгу автора (Hogan James P)

some change in diet maybe...something like that."
Danchekker shook his head decisively. "No. I say it's impossible." He
raised his hands and proceeded to count points off on his fingers. "One --
even if it did mutate, we'd still be able to identify its basic family
architecture in the same way we can identify the fundamental properties of,
say, any vertebrate. We can't.
"Two -- if it occurred only in one species of Oligocene animal, then I
would be prepared to concede that perhaps the enzyme we see here had mutated
and given rise to many strains that we find in the world today -- in other
words this strain represents an ancestral form common to a whole modern
family. If such were the case, then perhaps I'd agree that a mutation could
have occurred that was so severe that the relationship between the ancestral
strain and its descendants has been obscured. But that is not the case. This
same enzyme is found in many different and nonrelated Oilgocene species. For
your suggestion to apply, the same improbable process would have had to occur
many times over, independently, and all at the same time. I say that's
impossible."
"But..." Carpenter began, but Danchekker pressed on.
"Three -- none of today's animals possesses such an enzyme in its
microchemistry yet they all manage perfectly well without it. Many of them are
direct descendants of Oligocene types from the Ganymean ship. Now some of
those chains of descent have involved rapid mutation and adaptation to meet
changing diets and environments while others have not. In several cases the
evolution from Oligocene ancestors to today's forms has been very slow and has
produced only a small degree of change. We have made detailed comparisons
between the microchemical processes of such ancestral Oligocene ancestors
recovered from the ship and known data relating to animals that exist today
and are descended from those same ancestors. The results have been very much
as we expected -- no great changes and clearly identifiable relationships
between one group and the other. Every function that appeared in the
microchemistry of the ancestor could be easily recognized, sometimes with
slight modifications, in the descendants." Danchekker shot a quick glance at
Fichter. "Twenty-five million years isn't really so long on an evolutionary
time scale."
When no one seemed ready to object, Danchekker forged ahead. "But in
every case there was one exception -- this enzyme. Everything tells us that if
this enzyme were present in the ancestor, then it, or something very like it,
should be readily observable in the descendants. Yet in every case the results
have been negative. I say that cannot happen, and yet it has happened."
A brief silence descended while the group digested Danchekker's words.
At length Sandy Holmes ventured a thought. "Couldn't it still be a radical
mutation, but the other way around?"
 Danchekker frowned at her.
"How do you mean, the other way around?" asked Henri Rousson, another
senior biologist, seated next to Carpenter.
"Well," she replied, "all the animals on the ship had been to Minerva,
hadn't they? Most likely they were born there from ancestors the Ganymeans had
transported from Earth. Couldn't something in the Minervan environment have
caused a mutation that resulted in this enzyme? At least that would explain
why none of today's terrestrial animals have it. They've never been to Minerva