Red Mars(83)

While inside a thick, blinding cloud, she nearly shuffled right into one of the transponders, standing there like a fat fence post. “Hey!” she shouted.

“What’s wrong?”

“Nothing! I scared myself running into the roadmark.”

“You found it!”

“Yeah.” She felt her exhaustion run down into her hands and feet. She sat on the ground for a minute, then stood again; it was too cold to sit. Her ghost finger hurt.

She took up the nylon line and returned blindly to the dirigible, feeling she had wandered into the ancient myth, and was following the only thread out of the labyrinth.

• • •



During their rover trip south, blind in the flying dust, word came crackling over the radio that UNOMA had just approved and funded the establishment of three follow-up colonies. Each would consist of 500 people, all to be from countries not represented in the first hundred.

And the subcommittee on terraforming had recommended, and the General Assembly approved, a whole package of terraforming efforts, among them the distribution on the surface of genetically engineered microorganisms constructed from parent stock such as algaes, bacteria, or lichens.

Arkady laughed for a good thirty seconds. “Those bastards, those lucky bastards! They’re going to get away with it.”





Part 4



Homesick





One winter morning the sun shines down on Valles Marineris, illuminating the north walls of all the canyons in that great concatenation of canyons. And in that bright light one can see that here and there a ledge or outcropping is touched by a warty speck of black lichen.Life adapts, you see. It has only a few needs, some fuel, some energy; and it is fantastically ingenious at extracting these needs from a wide range of Terran environments. Some organisms live always below the freezing point of water, others above the boiling point; some live in high radiation zones, others in intensely salty regions, or within solid rock, or in pitch black, or in extreme dehydration, or without oxygen. All kinds of environments are accommodated, by adaptive measures so strange and marvelous they are beyond our capacity to imagine; and so from the bedrock to high in the atmosphere, life has permeated the Earth with the full weave of one great biosphere.

All these adaptive abilities are coded and passed along in genes. If the genes mutate, the organisms change. If the genes are altered, the organisms change. Bioengineers use both these forms of change, not only recombinant gene splicing, but also the much older art of selective breeding. Microorganisms are plated, and the fastest growers (or those that exhibit most the trait you want) can be culled and plated again; mutagens can be added to increase the mutation rate; and in the quick succession of microbial generations (say ten per day), you can repeat this process until you get something like what you want. Selective breeding is one of the most powerful bioengineering techniques we have.

But the newer techniques tend to get the attention. Genetically engineered microorganisms, or GEMs, had been on the scene only about half a century when the first hundred arrived on Mars. But half a century in modern science is a long time. Plasmid conjugates had become very sophisticated tools in those years. The array of restriction enzymes for cutting, and ligase enzymes for pasting, was big and versatile; the ability to line out long DNA strings precisely was there; the accumulated knowledge of genomes was immense, and growing exponentially; and used all together, this new biotechnology was allowing all kinds of trait mobilization, promotion, replication, triggered suicide (to stop excess success), and so forth. It was possible to find the DNA sequences from an organism that carried the desired characteristic, and then synthesize these DNA messages and cut and paste them into plasmid rings; after that cells were washed and suspended in a glycerol with the new plasmids, and the glycerol was suspended between two electrodes and given a short sharp shock of about 2,000 volts, and the plasmids in the gycerol shot into the cells, and voilá! There, zapped to life like Frankenstein’s monster, was a new organism. With new abilities.

And so: fast-growing lichens. Radiation-resistant algae, Extreme-cold fungi. Halophylic Archaea, eating salt and excreting oxygen. Surarctic mosses. An entire taxonomy of new kinds of life, all partially adapted to the surface of Mars, all out there having a try at it. Some species went extinct: natural selection. Some prospered: survival of the fittest. Some prospered wildly, at the expense of other organisms, and then chemicals in their excretions activated their suicide genes, and they died back until the levels of those chemicals dropped again.

So life adapts to conditions. And at the same time, conditions are changed by life. That is one of the definitions of life: organism and environment change together in a reciprocal arrangement, as they are two manifestations of an ecology, two parts of a whole.