The Tyrians evolved as they lived — as they had to, given that they lived for such a very long time. Every now and again, they would get together and exchange resources, but not in the simple binary combinations of human sexual intercourse. Tyrians “pupated” in groups of eight or more, immersing themselves within the massive pyramidal structures that were their own natural SusAn technology, so that their unconscious selves could become fluid, trading chimerical components and forging new, fully grown individuals.
Alice assured us that if this seemed flagrantly promiscuous to us, it was nothing compared to what less complex Tyrian organisms were wont to do. The Tyrian sentients, and their quasi-mammalian kin, kept to themselves because they had minds as well as bodies to maintain, but less intelligent organisms — creatures formed like various kinds of Earthly worms and mollusks — enjoyed far greater ubiquity. The advantages of this exotic biology had allowed the local soft-bodied animals to enjoy far greater success than their Earthly kin, to the extent that vertebrates were much rarer and more marginal, and insects had never evolved at all.
All of which would have been no more than mildly interesting, story-wise, had the plot not been thickened by two further elements.
Whereas the Earthly ecosphere only has one family of fundamental genetic molecules — comprising DNA and its close variant RNA — the Tyrian ecosphere had two. One was a “DNA-analog” which, in purely chemical terms, was a distant cousin to our own and to a number of other analogs animating primitive ecospheres on other worlds. The other was quite different, and so far unique.
I’m no biologist so I didn’t find it easy to follow the explanation Alice gave, but I think I got the gist of it.
The reproduction of Earthly organisms is a very complicated process, but it has two fundamental components: the reproduction of raw materials and the reproduction of anatomy. What genes do, for the most part, is provide blueprints for all the proteins that make up our bodies. Different kinds of cells use the blueprints in subtly different ways, producing slightly different sets of products, with those common to numerous cell types sometimes being produced in different quantities. The different cell types then have to be arranged into tissues and organs, and these too have to be distributed according to an anatomical scheme.
You might expect that the blueprint for bodily form would also have to be chemically coded into a set of genes, but it’s not as straightforward as that. There are bits of DNA whose function is to regulate the productivity of other bits of DNA, so that cells can be differentiated into a series of functional types, but the switching system is a simple one. In the same way, there are bits of DNA that are implicated in the way that different cell types are aggregated into tissues and organs, but their control system is also fairly simple. The process which determines whether an Earthly egg cell produces a cell mass that develops into a man, a bee, a crab, or an ostrich, consists of subtly different modifications of a surprisingly simple set of rules, whose application and enforcement have a lot to do with the environment in which the egg cell produces its embryo.
Figuring out how to simulate and direct an appropriate embryonic environment in an artificial womb was the breakthrough that made Conrad Helier a hero. The genes involved in the process are known as homeotic genes, and because they’re clustered together the whole outfit is sometimes called a “homeobox.” On Tyre, where the whole system works differently — because there is no process of embryonic development — the local equivalent of the homeobox isn’t just a few extra bits of DNA thrown in with all the rest; it’s a whole other ballgame. On Tyre, the biochemical system determining the form of organisms is quite separate and distinct from the DNA-analog system providing the raw materials out of which bodies are built.
The existence of the Tyrian example broadened the scope of comparative genomics considerably, and opened up the prospect of genomic engineering: the possibility that Earthly genomes might be remodelled at the most basic level so as to broaden the options open to artificial organisms. More profoundly, it opened up the possibility of genomic hybridization: of combining Tyrian-style homeoboxes with Earth-style chromosomes. The basis for some such technology was already present within the physiological processes organizing the chimerization of Tyrian organisms.
To put it crudely, once humans had arrived on Tyre there was a possibility — imaginatively farfetched but seemingly practicable — that Tyrian chimeras might be persuaded to take on DNA components, thus generating components of a hybrid ecosystem. The problems involved in persuading Tyrian soil to grow crops capable of nourishing human beings might be solved at a stroke. In the longer term, the possibility seemed to exist of arranging a more intimate exchange of potentials between human beings and the Tyrian sentients than had ever been envisaged.
In particular, the possibility seemed to exist that human beings might become chimeras themselves, taking on some of the attributes of their Tyrian comrades — most importantly, their natural emortality. That would have been a far more exciting prospect if the people of Earth hadn’t already figured out a way to confer their own kind of natural emortality upon their offspring, but it seemed exciting enough to the people of Tyre. Which brings us to the second ingredient thickening Alice’s plot.
When Matthew Fleury’s movie of the Tyrian contact was broadcast to Earth, the transmission reached other ears. It was broadcast along with a desperate appeal for technical support, to which Earth responded in its own time, at its own pace — but there was another source capable of offering that support, more rapidly and on a more generous scale.
Alice had no idea when or where the first ultrasmart machines had awakened to self-consciousness, but she suspected that the first self-sufficient colonies of such machines were the descendants of state-of-the-art space probes sent out to map and explore the nearer territories of the galaxy. They were self-replicating machines which also had the capacity to build many other kinds of machines, and to design others. They also had the capability to keep in touch with one another, exchanging the information they gathered. They were always likely candidates to make the transition to self-consciousness, if any machines were capable of it. The more remarkable thing, I suppose, is that they were the ones who chose to make their own first contact with their own makers — but given that the choice was made, where better to make that contact than Tyre? The Tyrians were in need of all kinds of produce that the machines could gather and manufacture, and were already practiced in the rare art of making and managing a first contact.
So the secrets of Earthly emortality were first delivered to Tyre not by the people of the home system, but by the mechanical colonizers of a system close enough to qualify — by galactic standards — as a near neighbor. The people of Tyre were only too pleased to add a second first contact to their first, and to maintain confidentiality not merely about the nature of that second first contact but the fact of its occurrence.
And that was the general shape of the wonderland into which Alice had been reborn after her long sojourn in ice.
Thirty-Two
Alice’s Story Continued
The first technologies of life extension gifted to Michelle and Alice Fleury by courtesy of their ultrasmart AMIs were nanotech repair facilities similar in kind to my own. They were intended as interim measures, until something better could be developed. Almost as soon as she was awakened, Alice discovered that she was expected to be among the volunteers for the first experiments in emortalization based on Tyre-derived biotechnologies. Although this prospect caused her some anxiety, she went with the flow. Given the enormous effort already invested by her father and sister, it really did seem to be a matter of destiny.